Nickel-Catalyzed Reductive Cross-Coupling of Chlorobismuths with Aryl Halides

Dedication

Dedicated to Professor Paul Knochel on the occasion of his 70th birthday.

Abstract

A straightforward and efficient method for the synthesis of valuable arylbismuthanes via nickel-catalyzed cross-electrophilic coupling of chlorobismuths with aryl halides has been reported. This cross-electrophile C(sp²)–Bi coupling reaction is conducted under mild reaction conditions and exhibits a broad substrate scope. Notably, the described protocol tolerates various sensitive functionalities including alcohol, nitrile, ester, ketone, and aldehyde. Moreover, the application of the generated arylbismuthanes to the Pd-catalyzed cross-coupling reaction is demonstrated.

Keywords

Cross-electrophilic coupling - Arylbismuthane - Aryl halide - C(sp²)–Bi coupling - Nickel catalyst

Bismuth[1] is a relatively inexpensive and low-toxic element, and bismuth compounds[2] are known for their low levels of toxicity, chemical stability, and high reactivity. It is for these reasons that numerous bismuth compounds exhibit important applications in the field of organometallic chemistry,[3] material science,[4] medicinal chemistry,[5] and organic synthesis.[6] For example, bismuth-based compounds have been extensively used as medicines to treat diseases such as cancers,[7] ulcers,[8] and gastrointestinal disorders[9] ([Scheme 1a]). Despite its appealing attributes and rich synthetic potential, organobismuth chemistry is far less developed than other main group organometallic chemistry due to the readily homolytic cleavage of the C–Bi bond[10] and the poor availability of organobismuth compounds. Especially, the efficient and general synthetic method for arylbismuthanes still remains a big challenge. In general, the C(sp²)–Bi bonds are constructed mainly by the transmetallation of R₂BiX with highly active aryl-Li or aryl-MgX ([Scheme 1b]).[11] However, these organometallic reagents may be accompanied by lower functional group tolerance and limited stability, which limits the practicability of this method. In 2020, Ball and coworkers reported a convenient new route to functionalized arylbismuthanes via B-to-Bi(iii) transmetallation from arylboronic acids ([Scheme 1b]).[12] In addition, heteroleptic triarylbismuthanes could be synthesized utilizing direct arylations of Ar₂BiX (X = OTs or I) with organozinc reagents ([Scheme 1b]).[13] Although the compatibility with sensitive functional groups has been improved by using arylboronic acids and organozinc reagents, additional steps are still required to prepare these organometallic reagents.

Scheme 1 Examples of bioactive bismuth compounds and the formation of C(sp²)–Bi bond.

In recent years, transition metal–catalyzed cross-electrophilic coupling (XEC) between two electrophiles has provided a revolutionary way to synthesize molecules with high step-efficiency and intriguing selectivity.[14] Unlike the conventional coupling, this method avoids the handling of sensitive organometallic species. While different C–C bond formations have been achieved in the field of XEC, C-heteroatom (Si, Ge, Sb, etc.) cross-couplings are much less advanced. In this context, Ni-catalyzed reductive C–Si,[15] C–Ge,[16] and C–Sb[17] cross-couplings have been developed recently. However, the construction of the C–Bi bond by means of transition metal–catalyzed XEC is less developed. While this study was in progress, a parallel report on the first Fe-catalyzed C(sp³)–Bi coupling of alkyl chlorides with chlorobismuthanes was published by Renhua Qiu and coworkers.[18] Hence, there is ample scope for the development of an efficient catalytic system for achieving C–Bi bond-forming XEC reactions. Herein, we reported Ni-catalyzed XEC of chlorobismuths with aryl halides, which can access arylbismuthanes with high functional group compatibility ([Scheme 1c]).

We began our investigations with a model reaction of chlorobismuth (1a) with 1-(4-bromophenyl)ethan-1-one (2a). After screening of a range of reaction conditions, we found that the combination of NiCl₂(dppf) (10 mol%), 1,10-phenanthroline (1,10-phen) (10 mol%), Mn (3 equiv), LiI (3 equiv), 4-dimethylaminopyridine (DMAP) (1 equiv), and DMA (2 mL) at 70 °C gave the best result, affording the corresponding arylbismuthane 3 in 73% isolated yield (entry 1, [Table 1]). The replacement of NiCl₂(dppf) by other nickel catalysts such as NiCl₂(dppp), NiI₂, and NiBr₂(dme) did not improve efficiency, giving arylbismuthane 3 in lower yields (entries 2–4, [Table 1]). The lithium iodide (LiI) that was supposed to facilitate the reduction of the nickel catalyst at the Mn surface was essential for this Ni-catalyzed cross-electrophile coupling of chlorobismuth with aryl halides,[19] and the corresponding arylbismuthane 3 was generated in lower yields when replacing LiI by LiCl or NaI (entries 5 and 6, [Table 1]). Through the screening of several general solvents, it was found that aprotic polar solvent dimethylacetamide (DMA) was the best choice of solvent for this catalytic system (entries 7–9, [Table 1]). As expected, the nature of the ligand had a tremendous effect on the reactivity, and bidentate nitrogen ligand 1,10-phen was found to be more beneficial for this transformation. Other ligands, including bipyridines and a phosphine ligand such as 1,1′-bis(diphenylphosphino)ferrocene (dppf), resulted in lower yields of 3 (entries 10–12, [Table 1]). It was also found that Mn reductant was essential for this Ni-catalyzed cross-electrophile coupling and could not be replaced with Zn powder that may cause the cleavage of the sensitive C–Bi bond in chlorobismuth 1a (entry 13, [Table 1]). In addition, the yield was not improved either by lowering or by elevating the reaction temperature (entries 14 and 15, [Table 1]). Meanwhile, control experiments confirmed the essentiality of the nickel catalyst, ligand, additive, and reductant for the successful XEC of chlorobismuth with aryl halides (entries 16–20, [Table 1]).

Table 1 Optimization of reaction conditions

Entry	Deviation from standard conditionsa	Yield of 3 (%)b
1	None	73
2	NiCl2(dppp) instead of NiCl2(dppf)	15
3	NiI2 instead of NiCl2(dppf)	11
4	NiBr2(dme) instead of NiCl2(dppf)	16
5	NaI instead of LiI	5
6	LiCl instead of LiI	19
7	NMP instead of DMA	9
8	DMF instead of DMA	8
9	Toluene instead of DMA	0
10	2,2′-Bipyridine instead of 1,10-phen	51
11	6,6′-Dimethyl-2,2′-dipyridyl instead of 1,10-phen	31
12	dppf instead of 1,10-phen	20
13	Zn instead of Mn	16
14	60 °C instead of 70 °C	58
15	90 °C instead of 70 °C	53
16	No NiCl2(dppf)	0
17	No 1,10-phen	0
18	No LiI	0
19	No Mn	0
20	No DMAP	63

^aStandard conditions: 1a (0.2 mmol), 2a (0.2 mmol), LiI (0.6 mmol), Mn (0.6 mmol), NiCl₂(dppf) (0.02 mmol, 10 mol%), 1,10-phenanthroline (0.02 mmol, 10 mol%), DMAP (0.2 mmol), DMA (2.0 mL), 70 °C, N₂, 12 h.

^bIsolated yield.

With the optimized reaction conditions in hand, a variety of aryl bromides were explored to react with chlorobismuth 1a. In general, aryl bromides with electron-poor, electron-neutral, or electron-rich substituents at different positions of the aryl ring could be well tolerated to deliver the desired arylbismuthanes 3–27 with good efficiency ([Scheme 2]). Interestingly, sensitive functional groups such as ketones, aldehydes, esters, and nitriles, which are conventionally incompatible with the highly active organometallic reagents (R-Li or R-MgX), were well tolerated in this transformation. Under the optimal conditions, these aryl bromides were successfully transformed into the expected products 3–13 in 24–73% yields, overcoming the limitations of traditional methods. Aryl bromides with functional groups such as fluorines and a trifluoromethyl group also gave the desired arylbismuthanes 14–16 in 44–51% yields. Notably, aryl bromides containing multiple sensitive functional groups could be coupled smoothly with chlorobismuth, affording stable, isolable arylbismuthanes 17 and 18. In addition, the reductive coupling of electron-neutral bromobenzene with chlorobismuth led to the corresponding product 19 in 87% yield. Similarly, 2-naphthyl bromide and 4-bromo-1,1′-biphenyl could be coupled to form products 20 and 21 in 22% and 47% yields, respectively. To our delight, reactions with aryl bromides containing mildly electron-donating groups (–Me, –OMe) provided arylbismuthanes 22 and 23 in 54% and 62% yields, respectively. Meanwhile, the cross-electrophile couplings of various heteroaryl bromides with chlorostibine 1a generated the target products 24–26 in 22−73% yields. In reactions that produced lower yields of products 18, 20, and 26, the balance of the mass was primarily the homocoupling of the aryl bromides. Remarkably, the amide functional group was well tolerated in this transformation, affording the expected product 27 in 65% yield.

Scheme 2 Substrate scope for the XEC of chlorobismuth with aryl bromides. Reaction conditions: 1a (0.2 mmol), aryl bromide (0.2 mmol), LiI (0.6 mmol), Mn (0.6 mmol), NiCl₂(dppf) (0.02 mmol, 10 mol%), 1,10-phenanthroline (0.02 mmol, 10 mol%), DMAP (0.2 mmol), DMA (2.0 mL), 70 °C, N₂, 12 h, isolated yield.

Other halides and pseudohalides such as aryl triflates, aryl iodides, and aryl chlorides were also found to be suitable substrates, which could react with chlorobismuth 1a to generate arylbismuthanes ([Scheme 3]). Triflate group has strong electronegativity, which makes the C–O bond difficult to convert into a C–metal bond from C–O bond cleavage. Under the standard reaction conditions, the XEC reaction of aryl triflates with chlorobismuth 1a proceeded smoothly, affording the desired product 3 in the yield of 61%. Moreover, reactions with aryl iodides generally resulted in higher yields. For instance, the yield of product 7 was increased from 24% to 43% when ethyl 4-iodobenzoate was employed as a substrate. Under the optimal conditions, isopropyl 3-iodobenzoate was also converted to the corresponding compound 28 in moderate yield. For product 11, yield was decreased from 70% to 34% when unactivated aryl chloride was used as a coupling substrate.

Scheme 3 Ni-catalyzed XEC of chlorobismuth with other aryl electrophiles. Reaction conditions: 1a (0.2 mmol), aryl halide or aryl triflate (0.2 mmol), LiI (0.6 mmol), Mn (0.6 mmol), NiCl₂(dppf) (0.02 mmol, 10 mol%), 1,10-phenanthroline (0.02 mmol, 10 mol%), DMAP (0.2 mmol), DMA (2.0 mL), 70 °C, N₂, 12 h, isolated yield.

To further investigate the practicability of this Ni-catalyzed C(sp²)–Bi bond-forming XEC reaction, we explored the reactivity of chlorobismuths. Under the standard conditions, both electron-donating groups (methyl) and electron-withdrawing groups (fluorine) attached to the nitrogen atom of chlorobismuths could be coupled with aryl bromides, affording the desired products 29–34 in 31–63% yields ([Scheme 4]). Functional groups such as ketone (29 and 33), ester (30), nitrile (31), and a methoxy group (32 and 34) were compatible with the reaction conditions, demonstrating the potential for the synthesis of versatile arylbismuthanes.

Scheme 4 Substrate scope for chlorobismuths. Reaction conditions: chlorobismuth (0.2 mmol), aryl bromide (0.2 mmol), LiI (0.6 mmol), Mn (0.6 mmol), NiCl₂(dppf) (0.02 mmol, 10 mol%), 1,10-phenanthroline (0.02 mmol, 10 mol%), DMAP (0.2 mmol), DMA (2.0 mL), 70 °C, N₂, 12 h, isolated yield.

To further explore the application of the synthesized arylbismuthanes, the cross-coupling of the generated arylbismuthane with aryl halide was conducted ([Scheme 5a]). In the presence of Pd(PPh₃)₄, the cross-coupling of arylbismuthane 19 with 1-(4-bromophenyl)ethan-1-one afforded the coupling product 35 in 47% yield. This Pd-catalyzed cross-coupling of the arylbismuthane demonstrates that there is a high potential to develop the arylbismuthanes as versatile arylation reagents. Moreover, the gram-scale synthesis of arylbismuthane 34 was achieved in 62% yield, which demonstrated the practicability of the Ni-catalyzed XEC reaction of chlorobismuths with aryl halides ([Scheme 5b]).

Scheme 5 Cross-coupling of arylbismuthane with aryl halide and gram-scale synthesis of arylbismuthane.

To reveal whether a radical process was involved in the Ni-catalyzed C(sp²)–Bi bond-forming XEC reaction, several control experiments were performed ([Scheme 6]). The reaction was not inhibited by the addition of radical scavengers such as butylated hydroxytoluene (BHT). In the presence of ethene-1,1-diyldibenzene (3.0 equiv), the reaction of 1a and 2a did not result in any radical trapping side product 36. These results suggest that Bi-Cl may not be activated through a radical process.

Scheme 6 Radical trapping experiments.

On the basis of the above results and previous reports,[14d] [16a] [17a] we proposed a plausible catalytic cycle for this Ni-catalyzed XEC reaction of chlorobismuths with aryl halides ([Scheme 7]). The Ni⁰ species (A) could be in situ-generated in the presence of Mn through reduction processes. The oxidative addition of Ar–X to Ni⁰, followed by reduction with Mn, provides nucleophilic Ar–Ni^I species C. The subsequent oxidative addition of the intermediate C with Bi–Cl may afford complex D, which undergoes reductive elimination to afford the desired product E and the intermediate Ni^I (F). Finally, the intermediate F is reduced by Mn to A.

Scheme 7 Proposed mechanism.

In summary, we have demonstrated an efficient and attractive strategy for the construction of C(sp²)–Bi bond via nickel-catalyzed XEC of chlorobismuths with aryl halides. This protocol showed a broad substrate scope and was compatible with a wide range of functional groups, such as aldehydes, ketones, nitriles, haloarenes (F, and CF₃), and heteroarenes. Furthermore, the synthesized arylbismuthanes could be used as versatile air-stable arylation reagents toward C(sp²)–C(sp²) bond.[?tpb +9pt?]?>

General Information

All reagents were obtained from commercial suppliers and used without further purification. Commercially available anhydrous DMA was used as received without further distillation. All reactions were carried out under nitrogen atmosphere in flame-dried glassware. Syringes which were used to transfer anhydrous solvents or reagents were purged with nitrogen prior to use. Yields refer to isolated yields of compounds estimated to be >95% pure as determined by ¹H NMR (25 °C). NMR spectra were recorded on solutions in deuterated chloroform (CDCl₃) with residual chloroform (δ7.26 ppm for ¹H NMR and δ77.16 ppm for ¹³C NMR). Abbreviations for signal coupling are as follows: s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet, br., broad. ESI-QTOF-MS measurements were performed in the positive ion mode (m/z 50–2000 range). Column chromatographical purifications were performed using SiO₂ (200–300 mesh ASTM).

Procedures

Typical Procedure (TP1) for the Synthesis of Arylbismuthanes

To a clean, oven-dried, screw cap reaction tube was added LiI (0.6 mmol), Mn (0.6 mmol), NiCl₂(dppf) (0.02 mmol, 10 mol%), 1,10-phenanthroline (0.02 mmol, 10 mol%), bismuth chloride (0.2 mmol), aryl halide (0.2 mmol), DMAP (0.2 mmol), and DMA (2 mL) under nitrogen atmosphere. The reaction mixture was stirred at 70 °C in an oil bath for 12 h. Then, the reaction mixture was diluted with water (5 mL) and extracted with EtOAc (3 × 10 mL). The resultant organic layer was dried over anhydrous Na₂SO₄ and the solvent was evaporated under reduced pressure. The crude mixture was purified by silica gel column chromatography using petroleum ether/EtOAc as the eluting system.

1-(4-(6-Phenyl-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)phenyl)ethan-1-one (3)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 1-(4-bromophenyl)ethan-1-one (40 mg, 0.2 mmol) afforded the desired product 3 as a white solid (88 mg, 73%).

Mp 226–228 °C.

¹H NMR (600 MHz, CDCl₃) δ 8.03–7.90 (m, 4H), 7.52 (d, J = 7.3 Hz, 2H), 7.37 (d, J = 7.5 Hz, 2H), 7.33–7.27 (m, 2H), 7.26–7.22 (m, 2H), 7.17 (t, J = 7.3 Hz, 2H), 7.09 (d, J = 8.2 Hz, 2H), 6.93 (t, J = 7.3 Hz, 1H), 4.75 (d, J = 15.2 Hz, 2H), 4.44 (d, J = 15.2 Hz, 2H), 2.65 (s, 3H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 199.0, 170.7, 152.5, 148.9, 146.2, 139.9, 139.3, 136.6, 130.1, 129.4, 129.3, 128.4, 127.9, 121.3, 117.4, 59.1, 26.8.

IR (Diamond-ATR, neat) 2991, 1665, 1576, 1503, 1265, 755, 690 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₈H₂₅BiNO [M + H]⁺ 600.1740, found 600.1727.

1-(3-(6-Phenyl-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)phenyl)ethan-1-one (4)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 1-(3-bromophenyl)ethan-1-one (40 mg, 0.2 mmol) afforded the desired product 4 as a white solid (68 mg, 57%).

Mp 188–190 °C.

¹H NMR (600 MHz, CDCl₃) δ 8.44 (s, 1H), 8.06–7.96 (m, 2H), 7.57–7.51 (m, 3H), 7.39 (d, J = 6.8 Hz, 2H), 7.34–7.28 (m, 2H), 7.27–7.23 (m, 2H), 7.21–7.16 (m, 2H), 7.13–7.08 (m, 2H), 6.94 (t, J = 7.3 Hz, 1H), 4.77 (d, J = 15.2 Hz, 2H), 4.46 (d, J = 15.3 Hz, 2H), 2.58 (s, 3H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 199.1, 163.2, 152.6, 148.9, 146.3, 144.7, 139.4, 139.2, 138.4, 130.4, 130.1, 129.3, 128.4, 127.9, 127.7, 121.3, 117.4, 59.1, 26.9.

IR (Diamond-ATR, neat) 2935, 1669, 1504, 1257, 749, 685 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₈H₂₅BiNO [M + H]⁺ 600.1740, found 600.1732.

Phenyl(4-(6-phenyl-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)phenyl)methanone (5)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 4-bromobenzonitrile (52 mg, 0.2 mmol) afforded the desired product 5 as a white solid (69 mg, 52%).

Mp 185–187 °C.

¹H NMR (600 MHz, CDCl₃) δ 7.97 (d, J = 7.2 Hz, 2H), 7.91–7.83 (m, 4H), 7.59 (d, J = 7.5 Hz, 3H), 7.51 (t, J = 7.6 Hz, 2H), 7.38 (d, J = 7.5 Hz, 2H), 7.31 (t, J = 7.4 Hz, 2H), 7.24 (d, J = 8.2 Hz, 2H), 7.20 (t, J = 7.4 Hz, 2H), 7.10 (d, J = 8.1 Hz, 2H), 6.93 (t, J = 7.3 Hz, 1H), 4.76 (d, J = 15.2 Hz, 2H), 4.45 (d, J = 15.2 Hz, 2H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 197.5, 169.7, 152.5, 148.9, 146.2, 139.6, 139.4, 137.9, 136.9, 132.5, 131.3, 130.3, 130.1, 129.3, 128.4, 128.4, 127.9, 121.3, 117.4, 59.1.

IR (Diamond-ATR, neat) 3054, 2900, 1649, 1573, 1493, 1271, 919, 746, 645 cm⁻¹.

HRMS (ESI⁺) calcd for C₃₃H₂₇BiNO [M + H]⁺ 662.1896, found 662.1884.

4-(6-Phenyl-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)benzaldehyde (6)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 4-bromobenzaldehyde (37 mg, 0.2 mmol) afforded the desired product 6 as a white solid (65 mg, 55%).

Mp 184–186 °C.

¹H NMR (600 MHz, CDCl₃) δ 10.05 (s, 1H), 8.04 (d, J = 7.3 Hz, 2H), 7.91 (d, J = 7.3 Hz, 2H), 7.51 (d, J = 7.4 Hz, 2H), 7.38 (d, J = 7.6 Hz, 2H), 7.31 (t, J = 7.5 Hz, 2H), 7.26–7.22 (m, 2H), 7.18 (t, J = 7.5 Hz, 2H), 7.10 (d, J = 8.0 Hz, 2H), 6.93 (t, J = 7.4 Hz, 1H), 4.75 (d, J = 15.3 Hz, 2H), 4.45 (d, J = 15.3 Hz, 2H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 193.2, 172.9, 152.8, 148.9, 146.2, 140.3, 139.3, 135.8, 130.8, 130.1, 129.3, 128.5, 128.0, 121.4, 117.5, 59.1.

IR (Diamond-ATR, neat) 3046, 2905, 2359, 2337, 1695, 1573, 1495, 1200, 742, 667 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₇H₂₃BiNO [M + H]⁺ 586.1583, found 586.1579.

Ethyl 4-(6-phenyl-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)benzoate (7)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with ethyl 4-bromobenzoate (46 mg, 0.2 mmol) afforded the desired product 7 as a white solid (30 mg, 24%).

Mp 185–187 °C.

¹H NMR (600 MHz, CDCl₃) δ 8.10 (d, J = 7.6 Hz, 2H), 7.94 (d, J = 7.5 Hz, 2H), 7.54 (d, J = 7.4 Hz, 2H), 7.37 (d, J = 7.5 Hz, 2H), 7.30 (t, J = 7.4 Hz, 2H), 7.24 (t, J = 5.9 Hz, 2H), 7.17 (t, J = 7.3 Hz, 2H), 7.10 (d, J = 8.1 Hz, 2H), 6.93 (t, J = 7.3 Hz, 1H), 4.75 (d, J = 15.2 Hz, 2H), 4.47–4.39 (m, 4H), 1.43 (t, J = 7.2 Hz, 3H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 170.0, 167.4, 152.5, 148.9, 146.2, 139.7, 139.3, 130.7, 130.1, 129.9, 129.2, 128.4, 127.9, 121.2, 117.4, 61.0, 59.1, 14.5.

IR (Diamond-ATR, neat) 3049, 2926, 1709, 1583, 1496, 1276, 1100, 742, 686 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₉H₂₇BiNO₂ [M + H]⁺ 630.1846, found 630.1840.

Methyl 4-(6-phenyl-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)benzoate (8)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with methyl 4-bromobenzoate (43 mg, 0.2 mmol) afforded the desired product 8 as a white solid (75 mg, 61%).

Mp 186–188 °C.

¹H NMR (600 MHz, CDCl₃) δ 8.08 (d, J = 7.9 Hz, 2H), 7.94 (d, J = 7.5 Hz, 2H), 7.53 (d, J = 7.3 Hz, 2H), 7.37 (d, J = 7.5 Hz, 2H), 7.30 (t, J = 7.5 Hz, 2H), 7.26–7.22 (m, 2H), 7.17 (t, J = 7.3 Hz, 2H), 7.09 (d, J = 8.2 Hz, 2H), 6.93 (t, J = 7.3 Hz, 1H), 4.75 (d, J = 15.3 Hz, 2H), 4.44 (d, J = 15.2 Hz, 2H), 3.95 (s, 3H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 167.9, 163.2, 152.5, 148.9, 146.2, 139.7, 139.3, 130.7, 130.1, 129.5, 129.3, 128.4, 127.9, 121.3, 117.4, 59.1, 52.2.

IR (Diamond-ATR, neat) 3041, 2914, 1706, 1586, 1429, 1286, 1111, 758, 685 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₈H₂₅BiNO₂ [M + H]⁺ 616.1689, found 616.1677.

Methyl 3-(6-phenyl-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)benzoate (9)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with methyl 3-bromobenzoate (43 mg, 0.2 mmol) afforded the desired product 9 as a white solid (67 mg, 54%).

Mp 196–198 °C.

¹H NMR (600 MHz, CDCl₃) δ 8.54 (s, 1H), 8.08 (d, J = 8.0 Hz, 1H), 8.01 (d, J = 6.8 Hz, 1H), 7.56–7.49 (m, 3H), 7.37 (d, J = 7.5 Hz, 2H), 7.32–7.27 (m 2H), 7.26–7.22 (m 2H), 7.17 (t, J = 7.5 Hz, 2H), 7.13–7.07 (m, 2H), 6.93 (t, J = 7.3 Hz, 1H), 4.75 (d, J = 15.2 Hz, 2H), 4.45 (d, J = 15.2 Hz, 2H), 3.90 (s, 3H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 167.9, 162.9, 152.5, 148.9, 146.2, 144.5, 140.3, 139.3, 131.4, 130.3, 130.1, 129.3, 129.1, 128.4, 127.9, 121.2, 117.5, 59.1, 52.2.

IR (Diamond-ATR, neat) 3051, 2924, 1708, 1584, 1497, 1263, 1109, 748, 690 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₈H₂₅BiNO₂ [M + H]⁺ 616.1689, found 616.1679.

5-(6-Phenyl-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)isobenzofuran-1(3H)-one (10)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 5-bromoisobenzofuran-1(3H)-one (43 mg, 0.2 mmol) afforded the desired product 10 as a white solid (90 mg, 73%).

Mp 186–188 °C.

¹H NMR (600 MHz, CDCl₃) δ 8.01 (d, J = 8.2 Hz, 2H), 7.94 (d, J = 7.5 Hz, 1H), 7.46 (d, J = 7.4 Hz, 2H), 7.39 (d, J = 7.5 Hz, 2H), 7.31 (t, J = 7.5 Hz, 2H), 7.26–7.22 (m, 2H), 7.18 (t, J = 7.4 Hz, 2H), 7.10 (d, J = 8.1 Hz, 2H), 6.94 (t, J = 7.4 Hz, 1H), 5.32 (s, 2H), 4.76 (d, J = 15.3 Hz, 2H), 4.45 (d, J = 15.3 Hz, 2H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 171.9, 153.1, 148.8, 148.0, 146.4, 140.1, 139.2, 134.1, 133.2, 130.2, 129.3, 128.6, 128.2, 126.7, 125.3, 121.6, 117.7, 69.9, 59.2.

IR (Diamond-ATR, neat) 2924, 1748, 1598, 1336, 1208, 742, 682 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₈H₂₃BiNO₂ [M + H]⁺ 614.1533, found 614.1522.

4-(6-Phenyl-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)benzonitrile (11)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 4-bromobenzonitrile (36 mg, 0.2 mmol) afforded the desired product 11 as a white solid (82 mg, 70%).

Mp 205–207 °C.

¹H NMR (600 MHz, CDCl₃) δ 7.96 (d, J = 7.5 Hz, 2H), 7.67 (d, J = 7.5 Hz, 2H), 7.47 (d, J = 7.4 Hz, 2H), 7.39 (d, J = 7.5 Hz, 2H), 7.32 (t, J = 7.4 Hz, 2H), 7.25 (t, J = 7.9 Hz, 2H), 7.19 (t, J = 7.3 Hz, 2H), 7.10 (d, J = 8.1 Hz, 2H), 6.94 (t, J = 7.3 Hz, 1H), 4.75 (d, J = 15.2 Hz, 2H), 4.44 (d, J = 15.2 Hz, 2H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 170.3, 152.9, 148.8, 146.3, 140.2, 139.1, 132.9, 130.2, 129.3, 128.5, 128.1, 121.5, 119.6, 117.6, 111.3, 59.2.

IR (Diamond-ATR, neat) 3054, 2220, 1587, 1504, 1212, 1040, 751, 690 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₇H₂₂BiN₂ [M + H]⁺ 583.1587, found 583.1578.

3-(6-Phenyl-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)benzonitrile (12)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 3-bromobenzonitrile (36 mg, 0.2 mmol) afforded the desired product 12 as a white solid (82 mg, 70%).

Mp 212–214 °C.

¹H NMR (600 MHz, CDCl₃) δ 8.12 (s, 1H), 8.06 (d, J = 7.4 Hz, 1H), 7.69 (d, J = 7.7 Hz, 1H), 7.50 (t, J = 7.5 Hz, 1H), 7.46 (d, J = 7.4 Hz, 2H), 7.39 (d, J = 7.5 Hz, 2H), 7.34–7.30 (m, 2H), 7.26–7.23 (m, 2H), 7.20 (t, J = 7.4 Hz, 2H), 7.09 (d, J = 8.1 Hz, 2H), 6.94 (t, J = 7.3 Hz, 1H), 4.75 (d, J = 15.2 Hz, 2H), 4.45 (d, J = 15.2 Hz, 2H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 166.3, 152.9, 148.8, 146.3, 143.9, 142.9, 139.1, 131.4, 130.3, 130.2, 129.3, 128.6, 128.2, 121.6, 119.7, 117.6, 114.3, 59.2.

IR (Diamond-ATR, neat) 3041, 2220, 1598, 1491, 1216, 748, 690 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₇H₂₂BiN₂ [M + H]⁺ 583.1587, found 583.1584.

2-(6-Phenyl-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)benzonitrile (13)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 2-bromobenzonitrile (36 mg, 0.2 mmol) afforded the desired product 13 as a white solid (49 mg, 42%).

Mp 231–233 °C.

¹H NMR (600 MHz, CDCl₃) δ 7.97 (d, J = 7.4 Hz, 1H), 7.79 (d, J = 7.7 Hz, 1H), 7.55 (t, J = 7.4 Hz, 1H), 7.50–7.43 (m, 3H), 7.39 (d, J = 7.5 Hz, 2H), 7.31 (t, J = 7.4 Hz, 2H), 7.26–7.21 (m, 2H), 7.18 (t, J = 7.4 Hz, 2H), 7.12 (d, J = 8.1 Hz, 2H), 6.95 (t, J = 7.3 Hz, 1H), 4.77 (d, J = 15.2 Hz, 2H), 4.46 (d, J = 15.2 Hz, 2H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 169.8, 154.8, 148.6, 146.6, 141.7, 139.4, 134.4, 133.1, 130.2, 129.3, 128.5, 128.2, 128.1, 122.2, 121.9, 120.9, 118.0, 59.4.

IR (Diamond-ATR, neat) 3189, 2212, 1648, 1419, 1102, 759 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₇H₂₂BiN₂ [M + H]⁺ 583.1587, found 583.1580.

12-(4-Fluorophenyl)-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (14)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 1-bromo-4-fluorobenzene (35 mg, 0.2 mmol) afforded the desired product 14 as a white solid (52 mg, 45%).

Mp 194–196 °C.

¹H NMR (600 MHz, CDCl₃) δ 7.79–7.71 (m, 2H), 7.54 (d, J = 7.4 Hz, 2H), 7.34 (d, J = 7.5 Hz, 2H), 7.30–7.25 m, 2H), 7.24–7.20 (m, 2H), 7.19–7.14 (m, 2H), 7.13–7.08 (m, 2H), 7.06 (d, J = 8.1 Hz, 2H), 6.90 (t, J = 7.3 Hz, 1H), 4.72 (d, J = 15.2 Hz, 2H), 4.41 (d, J = 15.2 Hz, 2H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 162.9 (d, J = 246.3 Hz), 157.4, 152.2, 149.0, 146.2, 141.4 (d, J = 6.7 Hz), 139.2, 129.9, 129.2, 128.3, 127.9, 121.1, 117.6 (d, J = 19.2 Hz), 117.3, 59.0.

IR (Diamond-ATR, neat) 3054, 1598, 1501, 1208, 1150, 814, 748, 690 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₆H₂₂BiFN [M + H]⁺ 576.1540, found 576.1532.

12-(3-Fluorophenyl)-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (15)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 1-bromo-3-fluorobenzene (35 mg, 0.2 mmol) afforded the desired product 15 as a white solid (59 mg, 51%).

Mp 227–229 °C.

¹H NMR (600 MHz, CDCl₃) δ 7.60–7.54 (m, 4H), 7.45–7.40 (m, 1H), 7.36 (d, J = 7.5 Hz, 2H), 7.32–7.27 (m, 2H), 7.25–7.22 (m, 2H), 7.18 (t, J = 7.3 Hz, 2H), 7.10–7.02 (m, 3H), 6.91 (t, J = 7.3 Hz, 1H), 4.73 (d, J = 15.2 Hz, 2H), 4.42 (d, J = 15.2 Hz, 2H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 164.9 (d, J = 252.1 Hz), 152.7, 148.9, 146.2, 139.3, 134.9 (d, J = 3.2 Hz), 131.5 (d, J = 6.2 Hz), 130.1, 129.3, 128.4, 127.9, 125.8, 125.7, 121.2, 117.4, 114.9 (d, J = 20.8 Hz), 59.1.

IR (Diamond-ATR, neat) 3027, 1570, 1504, 1195, 748, 690 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₆H₂₂BiFN [M + H]⁺ 576.1540, found 576.1530.

6-Phenyl-12-(3-(trifluoromethyl)phenyl)-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (16)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 1-bromo-3-(trifluoromethyl)benzene (45 mg, 0.2 mmol) afforded the desired product 16 as a white solid (55 mg, 44%).

Mp 171–173 °C.

¹H NMR (600 MHz, CDCl₃) δ 8.10 (s, 1H), 8.00 (d, J = 7.2 Hz, 1H), 7.64 (d, J = 7.7 Hz, 1H), 7.55–7.47 (m, 3H), 7.37 (d, J = 7.5 Hz, 2H), 7.29 (t, J = 7.5 Hz, 2H), 7.23 (d, J = 8.3 Hz, 2H), 7.17 (t, J = 7.5 Hz, 2H), 7.09 (d, J = 8.1 Hz, 2H), 6.92 (t, J = 7.5 Hz, 1H), 4.74 (d, J = 15.3 Hz, 2H), 4.44 (d, J = 15.3 Hz, 2H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 164.9, 152.7, 148.9, 146.3, 143.2, 139.2, 135.9 (d, J = 3.7 Hz), 130.18, 130.13, 129.3, 128.5, 128.0, 124.6 (q, J = 4.1 Hz), 124.5 (q, J = 274.5 Hz), 121.4, 117.5, 59.1.

IR (Diamond-ATR, neat) 3052, 1590, 1494, 1318, 1123, 752, 693 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₇H₂₂BiF₃N [M + H]⁺ 626.1508, found 626.1508.

2-Fluoro-4-(6-phenyl-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)benzonitrile (17)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 4-bromo-2-fluorobenzonitrile (40 mg, 0.2 mmol) afforded the desired product 17 as a white solid (37 mg, 31%).

Mp 187–189 °C.

¹H NMR (600 MHz, CDCl₃) δ 7.73 (dd, J = 10.1, 7.5 Hz, 2H), 7.66–7.60 (m, 1H), 7.45 (d, J = 7.4 Hz, 2H), 7.40 (d, J = 7.5 Hz, 2H), 7.33 (t, J = 7.5 Hz, 2H), 7.26–7.19 (m, 4H), 7.09 (d, J = 8.1 Hz, 2H), 6.95 (t, J = 7.4 Hz, 1H), 4.75 (d, J = 15.3 Hz, 2H), 4.44 (d, J = 15.3 Hz, 2H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 173.5, 164.3 (d, J = 265.5 Hz), 153.6, 148.6, 146.4, 139.1, 135.6 (d, J = 3.6 Hz), 134.1, 130.4, 129.3, 128.7, 128.3, 126.8 (d, J = 15.3 Hz), 121.9, 117.8, 114.7, 100.4 (d, J = 15.6 Hz), 59.3.

IR (Diamond-ATR, neat) 2917, 2234, 1590, 1491, 1216, 748, 687 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₇H₂₁BiFN₂ [M + H]⁺ 601.1493, found 601.1484.

1-(2-Hydroxy-4-(6-phenyl-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)phenyl)ethan-1-one (18)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 1-(4-bromo-2-hydroxyphenyl)ethan-1-one (43 mg, 0.2 mmol) afforded the desired product 18 as a white solid (25 mg, 20%).

Mp 188–189 °C.

¹H NMR (600 MHz, CDCl₃) δ 12.30 (s, 1H), 7.76 (d, J = 7.7 Hz, 1H), 7.64–7.53 (m, 3H), 7.41–7.35 (m, 3H), 7.31 (t, J = 7.4 Hz, 2H), 7.26–7.23 (m, 2H), 7.20 (t, J = 7.4 Hz, 2H), 7.09 (d, J = 8.1 Hz, 2H), 6.94 (t, J = 7.3 Hz, 1H), 4.75 (d, J = 15.2 Hz, 2H), 4.44 (d, J = 15.2 Hz, 2H), 2.67 (s, 3H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 205.0, 175.1, 162.9, 153.0, 148.9, 146.2, 139.4, 131.5, 130.1, 129.9, 129.28, 129.26, 128.5, 127.9, 121.4, 119.1, 117.5, 59.2, 26.7.

IR (Diamond-ATR, neat) 3395, 2914, 1625, 1504, 1257, 1020, 756, 683 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₈H₂₅BiNO₂ [M + H]⁺ 616.1689, found 616.1688.

6,12-Diphenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (19)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with bromobenzene (32 mg, 0.2 mmol) afforded the desired product 19 as a white solid (97 mg, 87%).

Mp 241–242 °C.

¹H NMR (600 MHz, CDCl₃) δ 7.83 (d, J = 7.0 Hz, 2H), 7.61 (d, J = 7.3 Hz, 2H), 7.46 (t, J = 7.3 Hz, 2H), 7.42 (d, J = 7.3 Hz, 1H), 7.36 (d, J = 7.6 Hz, 2H), 7.29 (t, J = 7.4 Hz, 2H), 7.26–7.21 (m, 2H), 7.17 (t, J = 7.4 Hz, 2H), 7.09 (d, J = 8.1 Hz, 2H), 6.91 (t, J = 7.4 Hz, 1H), 4.74 (d, J = 15.2 Hz, 2H), 4.44 (d, J = 15.2 Hz, 2H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 162.9, 152.2, 149.1, 146.1, 139.6, 139.4, 130.2, 129.9, 129.2, 128.3, 127.8, 120.9, 117.2, 58.9.

IR (Diamond-ATR, neat) 3054, 2920, 1590, 1497, 1213, 748 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₆H₂₃BiN [M + H]⁺ 558.1634, found 558.1629.

12-(Naphthalen-2-yl)-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (20)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 2-bromonaphthalene (42 mg, 0.2 mmol) afforded the desired product 20 as a white solid (27 mg, 22%).

Mp 242–244 °C.

¹H NMR (600 MHz, CDCl₃) δ 8.36 (s, 1H), 7.93–7.85 (m, 3H), 7.83 (d, J = 7.5 Hz, 1H), 7.61 (d, J = 7.4 Hz, 2H), 7.54–7.48 (m, 2H), 7.38 (d, J = 7.5 Hz, 2H), 7.31–7.25 (m, 4H), 7.16–7.08 (m, 4H), 6.93 (t, J = 7.3 Hz, 1H), 4.77 (d, J = 15.2 Hz, 2H), 4.47 (d, J = 15.2 Hz, 2H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 162.3, 152.4, 149.1, 146.2, 139.54, 139.50, 136.7, 135.2, 133.2, 129.9, 129.5, 129.2, 128.3, 128.1, 127.86, 127.84, 126.0, 125.9, 121.0, 117.3, 59.1.

IR (Diamond-ATR, neat) 3035, 2917, 1590, 1497, 1329, 1222, 751 cm⁻¹.

HRMS (ESI⁺) calcd for C₃₀H₂₅BiN [M + H]⁺ 608.1791, found 608.1785.

12-([1,1′-Biphenyl]-4-yl)-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (21)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 4-bromo-1,1′-biphenyl (47 mg, 0.2 mmol) afforded the desired product 21 as a white solid (60 mg, 47%).

Mp 203–205 °C.

¹H NMR (600 MHz, CDCl₃) δ 7.90 (d, J = 7.4 Hz, 2H), 7.73–7.64 (m, 6H), 7.46 (t, J = 7.6 Hz, 2H), 7.36 (d, J = 7.5 Hz, 3H), 7.30 (t, J = 7.4 Hz, 2H), 7.26–7.23 (m, 2H), 7.19 (t, J = 7.4 Hz, 2H), 7.10 (d, J = 8.1 Hz, 2H), 6.92 (t, J = 7.3 Hz, 1H), 4.75 (d, J = 15.2 Hz, 2H), 4.45 (d, J = 15.2 Hz, 2H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 161.9, 152.0, 149.1, 146.1, 141.5, 140.5, 140.1, 139.5, 129.9, 129.2, 128.9, 128.86, 128.3, 127.8, 127.4, 127.3, 120.9, 117.2, 59.0.

IR (Diamond-ATR, neat) 3027, 2910, 1590, 1494, 1322, 1219, 745, 679 cm⁻¹.

HRMS (ESI⁺) calcd for C₃₂H₂₇BiN [M + H]⁺ 634.1947, found 634.1948.

6-Phenyl-12-(m-tolyl)-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (22)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 1-bromo-3-methylbenzene (34 mg, 0.2 mmol) afforded the desired product 22 as a white solid (62 mg, 54%).

Mp 197–199 °C.

¹H NMR (600 MHz, CDCl₃) δ 7.67 (s, 1H), 7.66–7.60 (m, 3H), 7.40–7.34 (m, 3H), 7.29 (t, J = 7.4 Hz, 2H), 7.26–7.21 (m, 3H), 7.18 (t, J = 7.4 Hz, 2H), 7.09 (d, J = 8.1 Hz, 2H), 6.92 (t, J = 7.3 Hz, 1H), 4.74 (d, J = 15.2 Hz, 2H), 4.44 (d, J = 15.2 Hz, 2H), 2.38 (s, 3H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 162.8, 152.1, 149.1, 146.1, 140.1, 139.5, 139.4, 136.6, 130.1, 129.9, 129.2, 128.6, 128.2, 127.8, 120.9, 117.2, 58.9, 21.7.

IR (Diamond-ATR, neat) 3041, 2986, 1590, 1494, 1222, 751, 682 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₇H₂₅BiN [M + H]⁺ 572.1791, found 572.1785.

12-(3-Methoxyphenyl)-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (23)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 1-bromo-3-methoxybenzene (38 mg, 0.2 mmol) afforded the desired product 23 as a white solid (73 mg, 62%).

Mp 202–204 °C.

¹H NMR (600 MHz, CDCl₃) δ 7.66 (d, J = 7.4 Hz, 2H), 7.45–7.39 (m, 3H), 7.36 (d, J = 7.5 Hz, 2H), 7.31–7.27 (m, 2H), 7.26–7.22 (m, 2H), 7.19 (t, J = 7.4 Hz, 2H), 7.10 (d, J = 8.1 Hz, 2H), 6.97–6.89 (m, 2H), 4.75 (d, J = 15.2 Hz, 2H), 4.44 (d, J = 15.2 Hz, 2H), 3.79 (s, 3H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 164.0, 161.3, 152.4, 149.1, 146.2, 139.5, 131.7, 131.1, 129.9, 129.2, 128.3, 127.8, 124.4, 120.9, 117.3, 113.8, 59.0, 55.3.

IR (Diamond-ATR, neat) 3041, 2961, 1570, 1504, 1367, 1222, 755 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₇H₂₅BiNO [M + H]⁺ 588.1740, found 588.1730.

6-Phenyl-12-(quinolin-6-yl)-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (24)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 6-bromoquinoline (42 mg, 0.2 mmol) afforded the desired product 24 as a white solid (89 mg, 73%).

Mp 231–233 °C.

¹H NMR (600 MHz, CDCl₃) δ 8.93 (d, J = 4.3 Hz, 1H), 8.32 (s, 1H), 8.16–8.10 (m, 3H), 7.56 (d, J = 7.4 Hz, 2H), 7.42 (dd, J = 8.2, 4.3 Hz, 1H), 7.38 (d, J = 7.4 Hz, 2H), 7.31–7.27 (m, 2H), 7.27–7.22 (m, 2H), 7.15–7.09 (m, 4H), 6.93 (t, J = 7.3 Hz, 1H), 4.76 (d, J = 15.2 Hz, 2H), 4.46 (d, J = 15.3 Hz, 2H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 161.6, 152.4, 150.5, 149.0, 148.2, 146.2, 140.5, 139.4, 139.3, 135.9, 131.8, 130.8, 130.1, 129.3, 128.4, 127.9, 121.2, 119.2, 117.4, 59.1.

IR (Diamond-ATR, neat) 3034, 2917, 1587, 1488, 1219, 745 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₉H₂₄BiN₂ [M + H]⁺ 609.1743, found 609.1752.

12-(Benzo[b]thiophen-5-yl)-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (25)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 5-bromobenzo[b]thiophene (43 mg, 0.2 mmol) afforded the desired product 25 as a white solid (49 mg, 40%).

Mp 233–235 °C.

¹H NMR (600 MHz, CDCl₃) δ 8.33 (s, 1H), 7.96 (d, J = 7.9 Hz, 1H), 7.76 (d, J = 8.0 Hz, 1H), 7.61 (d, J = 7.4 Hz, 2H), 7.44 (d, J = 5.3 Hz, 1H), 7.39–7.31 (m, 3H), 7.30–7.22 (m, 4H), 7.14 (t, J = 7.6 Hz, 2H), 7.10 (d, J = 8.1 Hz, 2H), 6.92 (t, J = 7.5 Hz, 1H), 4.76 (d, J = 15.2 Hz, 2H), 4.46 (d, J = 15.2 Hz, 2H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 164.9, 157.9, 152.2, 149.1, 146.2, 141.7, 139.5, 135.3, 134.9, 129.9, 129.2, 128.3, 127.8, 125.8, 124.5, 124.1, 121.0, 117.3, 59.0.

IR (Diamond-ATR, neat) 2928, 1590, 1502, 1426, 1219, 748, 687 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₈H₂₃BiNS [M + H]⁺ 614.1355, found 614.1348.

6-Phenyl-12-(thiophen-3-yl)-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (26)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 3-bromothiophene (33 mg, 0.2 mmol) afforded the desired product 26 as a white solid (25 mg, 22%).

Mp 199–201 °C.

¹H NMR (600 MHz, CDCl₃) δ 7.61 (d, J = 7.3 Hz, 2H), 7.54 (s, 1H), 7.48 (d, J = 4.6 Hz, 1H), 7.31 (d, J = 7.3 Hz, 2H), 7.28–7.18 (m, 5H), 7.14 (t, J = 7.3 Hz, 2H), 7.05 (d, J = 8.1 Hz, 2H), 6.88 (t, J = 7.3 Hz, 1H), 4.70 (d, J = 15.2 Hz, 2H), 4.39 (d, J = 15.2 Hz, 2H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 163.5, 156.3, 149.0, 145.9, 139.6, 136.7, 134.6, 129.9, 129.2, 128.1, 127.9, 127.6, 121.2, 117.3, 58.9.

IR (Diamond-ATR, neat) 2993, 1601, 1505, 1271, 748 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₄H₂₁BiNS [M + H]⁺ 564.1199, found 564.1190.

N,N-Dimethyl-4-(6-phenyl-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)benzamide (27)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with 4-bromo-N,N-dimethylbenzamide (46 mg, 0.2 mmol) afforded the desired product 27 as a white solid (82 mg, 65%).

Mp 200–202 °C.

¹H NMR (600 MHz, CDCl₃) δ 7.86 (d, J = 7.3 Hz, 2H), 7.58 (d, J = 7.4 Hz, 2H), 7.48 (d, J = 7.4 Hz, 2H), 7.36 (d, J = 7.5 Hz, 2H), 7.32–7.27 (m, 2H), 7.26–7.21 (m, 2H), 7.20–7.15 (m, 2H), 7.09 (d, J = 8.1 Hz, 2H), 6.92 (t, J = 7.4 Hz, 1H), 4.74 (d, J = 15.2 Hz, 2H), 4.43 (d, J = 15.2 Hz, 2H), 3.15 (s, 3H), 3.07 (s, 3H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 172.2, 165.2, 152.3, 149.0, 146.2, 139.5, 139.4, 135.6, 130.0, 129.2, 128.6, 128.3, 127.9, 121.1, 117.3, 59.1, 39.9, 35.6.

IR (Diamond-ATR, neat) 3052, 2921, 1622, 1496, 1393, 1207, 1081, 827, 746, 686 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₉H₂₈BiN₂O [M + H]⁺ 629.2005, found 629.2014.

Isopropyl 3-(6-phenyl-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)benzoate (28)

According to TP1, the reaction of 12-chloro-6-phenyl-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (103 mg, 0.2 mmol) with isopropyl 3-Iodobenzoate (49 mg, 0.2 mmol) afforded the desired product 28 as a white solid (58 mg, 45%).

Mp 171–173 °C.

¹H NMR (600 MHz, CDCl₃) δ 8.54 (s, 1H), 8.08 (d, J = 7.7 Hz, 1H), 7.99 (d, J = 7.2 Hz, 1H), 7.57–7.49 (m, 3H), 7.37 (d, J = 7.5 Hz, 2H), 7.30 (t, J = 7.4 Hz, 2H), 7.25 (t, J = 7.2 Hz, 2H), 7.17 (t, J = 7.3 Hz, 2H), 7.10 (d, J = 8.1 Hz, 2H), 6.93 (t, J = 7.3 Hz, 1H), 7.30–7.22 (m, 1H), 4.76 (d, J = 15.2 Hz, 2H), 4.45 (d, J = 15.2 Hz, 2H), 1.37 (d, J = 6.2 Hz, 6H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 166.8, 162.9, 152.5, 148.9, 146.2, 144.4, 140.1, 139.3, 131.9, 130.3, 130.0, 129.2, 129.1, 128.4, 127.9, 121.2, 117.4, 68.4, 59.1, 22.1.

IR (Diamond-ATR, neat) 3041, 2924, 1703, 1594, 1494, 1282, 1098, 742, 690 cm⁻¹.

HRMS (ESI⁺) calcd for C₃₀H₂₉BiNO₂ [M + H]⁺ 644.2002, found 644.1998.

1-(4-(6-(p-Tolyl)-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)phenyl)ethan-1-one (29)

According to TP1, the reaction of 12-chloro-6-(p-tolyl)-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (106 mg, 0.2 mmol) with 1-(4-bromophenyl)ethan-1-one (40 mg, 0.2 mmol) afforded the desired product 29 as a white solid (77 mg, 63%).

Mp 211–213 °C.

¹H NMR (600 MHz, CDCl₃) δ 8.07–7.98 (m, 4H), 7.54 (d, J = 7.4 Hz, 2H), 7.37 (d, J = 7.5 Hz, 2H), 7.33–7.27 (m, 2H), 7.22–7.14 (m, 2H), 7.10–6.98 (m, 4H), 4.71 (d, J = 15.2 Hz, 2H), 4.43 (d, J = 15.2 Hz, 2H), 2.66 (s, 3H), 2.26 (s, 3H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 199.1, 171.1, 152.7, 146.5, 146.3, 139.9, 139.3, 136.5, 130.8, 130.0, 129.8, 129.4, 128.4, 127.9, 117.6, 59.3, 26.8, 20.6.

IR (Diamond-ATR, neat) 2917, 1673, 1508, 1356, 1268, 811, 751, 594 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₉H₂₇BiNO [M + H]⁺ 614.1896, found 614.1886.

Methyl 4-(6-(p-tolyl)-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)benzoate (30)

According to TP1, the reaction of 12-chloro-6-(p-tolyl)-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (106 mg, 0.2 mmol) with ethyl 4-bromobenzoate (43 mg, 0.2 mmol) afforded the desired product 30 as a white solid (46 mg, 37%).

Mp 200–202 °C.

¹H NMR (600 MHz, CDCl₃) δ 8.08 (d, J = 7.4 Hz, 2H), 7.95 (d, J = 7.4 Hz, 2H), 7.53 (d, J = 7.4 Hz, 2H), 7.36 (d, J = 7.5 Hz, 2H), 7.29 (t, J = 7.5 Hz, 2H), 7.17 (t, J = 7.4 Hz, 2H), 7.10–6.96 (m, 4H), 4.70 (d, J = 15.2 Hz, 2H), 4.42 (d, J = 15.2 Hz, 2H), 3.95 (s, 3H), 2.26 (s, 3H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 170.5, 167.9, 152.7, 146.5, 146.3, 139.7, 139.3, 130.8, 130.7, 130.0, 129.8, 129.4, 128.4, 127.9, 117.6, 59.3, 52.2, 20.6.

IR (Diamond-ATR, neat) 3043, 2920, 1710, 1591, 1326, 756 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₉H₂₇BiNO₂ [M + H]⁺ 630.1846, found 630.1841.

4-(6-(p-Tolyl)-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)benzonitrile (31)

According to TP1, the reaction of 12-chloro-6-(p-tolyl)-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (106 mg, 0.2 mmol) with 4-bromobenzonitrile (36 mg, 0.2 mmol) afforded the desired product 31 as a white solid (62 mg, 52%).

Mp 220–222 °C.

¹H NMR (600 MHz, CDCl₃) δ 7.99 (d, J = 7.4 Hz, 2H), 7.68 (d, J = 7.4 Hz, 2H), 7.48 (d, J = 6.9 Hz, 2H), 7.39 (d, J = 7.3 Hz, 2H), 7.33 (t, J = 7.3 Hz, 2H), 7.21 (t, J = 7.3 Hz, 2H), 7.13–6.98 (m, 4H), 4.72 (d, J = 15.3 Hz, 2H), 4.43 (d, J = 15.3 Hz, 2H), 2.28 (s, 3H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 170.7, 153.1, 146.4, 146.3, 140.2, 139.1, 132.9, 131.1, 130.1, 129.8, 128.5, 128.1, 119.6, 117.8, 111.2, 59.4, 20.5.

IR (Diamond-ATR, neat) 2914, 2220, 1511, 1353, 1199, 820, 752 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₈H₂₄BiN₂ [M + H]⁺ 597.1743, found 597.1743.

12-(3-Methoxyphenyl)-6-(p-tolyl)-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (32)

According to TP1, the reaction of 12-chloro-6-(p-tolyl)-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (106 mg, 0.2 mmol) with 1-bromo-3-methoxybenzene (38 mg, 0.2 mmol) afforded the desired product 32 as a white solid (40 mg, 33%).

Mp 210–212 °C.

¹H NMR (600 MHz, CDCl₃) δ 7.65 (d, J = 7.3 Hz, 2H), 7.46–7.39 (m, 3H), 7.35 (d, J = 7.5 Hz, 2H), 7.29 (t, J = 7.4 Hz, 2H), 7.18 (t, J = 7.3 Hz, 2H), 7.09–6.99 (m, 4H), 6.97–6.91 (m, 1H), 4.70 (d, J = 15.2 Hz, 2H), 4.41 (d, J = 15.2 Hz, 2H), 3.79 (s, 3H), 2.27 (s, 3H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 164.4, 161.3, 152.5, 146.7, 146.3, 139.5, 131.7, 131.1, 130.4, 129.8, 129.8, 128.2, 127.7, 124.4, 117.5, 113.8, 59.3, 55.3, 20.5.

IR (Diamond-ATR, neat) 2993, 1580, 1511, 1370, 1229, 748 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₈H₂₇BiNO [M + H]⁺ 602.1896, found 602.1891.

1-(4-(6-(4-Fluorophenyl)-6,7-dihydrodibenzo[c,f][1,5]azabismocin-12(5H)-yl)phenyl)ethan-1-one (33)

According to TP1, the reaction of 12-chloro-6-(4-fluorophenyl)-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (107 mg, 0.2 mmol) with 1-(4-bromophenyl)ethan-1-one (40 mg, 0.2 mmol) afforded the desired product 33 as a white solid (38 mg, 31%).

Mp 194–196 °C.

¹H NMR (600 MHz, CDCl₃) δ 8.04–7.94 (m, 4H), 7.54 (d, J = 7.3 Hz, 2H), 7.36 (d, J = 7.5 Hz, 2H), 7.33–7.27 (m, 2H), 7.21–7.15 (m, 2H), 7.08–7.01 (m, 2H), 6.94 (t, J = 8.7 Hz, 2H), 4.65 (d, J = 15.1 Hz, 2H), 4.44 (d, J = 15.1 Hz, 2H), 2.65 (s, 3H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 199.0, 170.6, 157.9 (d, J = 240.8 Hz), 152.5, 145.9, 145.2, 139.9, 139.3, 136.6, 130.2, 129.5, 128.5, 128.0, 118.9 (d, J = 7.5 Hz), 115.8 (d, J = 22.2 Hz), 59.6, 26.8.

IR (Diamond-ATR, neat) 2920, 1680, 1505, 1357, 1219, 811, 748 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₈H₂₄BiFNO [M + H]⁺ 618.1646, found 618.1645.

6-(4-Fluorophenyl)-12-(3-methoxyphenyl)-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (34)

According to TP1, the reaction of 12-chloro-6-(4-fluorophenyl)-5,6,7,12-tetrahydrodibenzo[c,f][1,5]azabismocine (107 mg, 0.2 mmol) with 1-bromo-3-methoxybenzene (38 mg, 0.2 mmol) afforded the desired product 34 as a white solid (53 mg, 44%).

Mp 176–178 °C.

¹H NMR (600 MHz, CDCl₃) δ 7.65 (d, J = 7.4 Hz, 2H), 7.46–7.38 (m, 3H), 7.34 (d, J = 7.4 Hz, 2H), 7.31–7.26 (m, 2H), 7.22–7.15 (m, 2H), 7.04 (d, J = 8.9 Hz, 2H), 6.98–6.87 (m, 3H), 4.63 (d, J = 15.1 Hz, 2H), 4.43 (d, J = 15.1 Hz, 2H), 3.79 (s, 3H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 170.5, 163.9, 157.8 (d, J = 240.0 Hz), 152.4, 145.9, 145.4, 139.5, 131.7, 131.1, 129.9, 128.3, 127.9, 124.5, 118.7 (d, J = 7.6 Hz), 115.7 (d, J = 22.2 Hz), 113.8, 59.5, 55.4.

IR (Diamond-ATR, neat) 2917, 1508, 1219, 817, 759 cm⁻¹.

HRMS (ESI⁺) calcd for C₂₇H₂₄BiFNO [M + H]⁺ 606.1646, found 606.1636.

1-([1,1′-Biphenyl]-4-yl)ethan-1-one (35)

To a clean, oven-dried, screw cap reaction tube was added the bismuth compound 19 (145 mg, 0.26 mmol), 1-(4-bromophenyl)ethan-1-one (40 mg, 0.2 mmol), Pd(PPh₃)₄ (23 mg, 0.02 mmol), Cs₂CO₃ (130 mg, 0.4 mmol), and NMP (2 mL) under nitrogen atmosphere. The reaction mixture was stirred at 100 °C in an oil bath for 12 h. Then, the reaction mixture was diluted with water (5 mL) and extracted with EtOAc (3 × 10 mL). The resultant organic layer was dried over anhydrous Na₂SO₄, and the solvent was evaporated under reduced pressure. The crude mixture was purified by silica gel column chromatography using petroleum ether/EtOAc as the eluting system, affording the corresponding product 35 as a white solid (39 mg, 47%).

¹H NMR (600 MHz, CDCl₃) δ 8.04 (d, J = 8.5 Hz, 2H), 7.69 (d, J = 8.1 Hz, 2H), 7.63 (d, J = 7.2 Hz, 2H), 7.50–7.45 (m, 2H), 7.43–7.38 (m, 1H), 2.64 (s, 3H).

¹³C{¹H} NMR (151 MHz, CDCl₃) δ 197.9, 145.9, 140.0, 136.0, 129.1, 129.1, 128.4, 127.42, 127.38, 26.8.

All the resonances in the ¹H and ^l3C NMR spectra were consistent with reported values.[20]

Conflict of Interest

The authors declare that they have no conflict of interest.

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Publication History

Received: 11 July 2025

Accepted after revision: 11 August 2025

Accepted Manuscript online:
12 August 2025

Article published online:
01 September 2025