Synlett 2024; 35(08): 925-929
DOI: 10.1055/a-2202-4667
cluster
Special Issue dedicated to Keith Fagnou

Synthesis of Axially Chiral Bibenzo[g]coumarin Derivatives by Rhodium-Catalyzed Oxidative Annulation of Thiocarbamates

Ryo Takishima
a   Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
,
Koushik Ghosh
a   Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
,
Yuji Nishii
a   Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
b   Center for Future Innovation, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
,
c   Innovative Catalysis Science Division, Institute for Open and Transitionary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan
› Author Affiliations
This research was supported by a Grant-in-Aid for Scientific Research from JSPS (Specially Promoted Research, Grant No. JP 17H06092).


Abstract

Polyaromatic organic compounds have attracted significant attention because of their wide range of applications in various functional materials. Recently, transition-metal-catalyzed C–H bond activation and the subsequent oxidative cyclization with unsaturated compounds has emerged as a promising synthetic method for multiring systems. We report a two-step synthesis of binaphthyl-fused chiral bibenzo[g]coumarin derivatives by Rh-catalyzed annulative coupling reaction of BINOL-based thiocarbamates with alkynes. The optical properties of the coupling products were evaluated.

Supporting Information



Publication History

Received: 28 August 2023

Accepted after revision: 01 November 2023

Accepted Manuscript online:
01 November 2023

Article published online:
14 December 2023

© 2023. Thieme. All rights reserved

Georg Thieme Verlag KG
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  • References and Notes

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  • 13 O,O′-1,1′-Binaphthalene-2,2′-diyl Bis[diethyl(thiocarbamate)] (1) A 20 mL two-necked round-bottomed flask equipped with a N2 balloon was charged with (S)- or (R)-BINOL (286 mg, 1.0 mmol), DABCO (224 mg, 2.0 mmol), and THF (3.0 mL). A 60% paraffin dispersion of NaH (120 mg, 3.0 mmol) was added in a portionwise manner, then diethylthiocarbamoyl chloride (334 mg, 2.2 mmol) was added dropwise from a syringe. The resulting mixture was stirred in an oil bath at 60 °C for 18 h, then poured into ice–water and extracted with CHCl3 (×3). The combined organic layer was washed with brine, dried (Na2SO4), and concentrated in vacuo. The residue was purified by column chromatography [silica gel, hexane–EtOAc (5:1)] to give a white solid; yield: (R)-1: 442 mg (86%); (S)-1: 429 mg (83%); mp 106–108 °C. HPLC [CHIRAL ART Amylose-SA column, hexane–CH3Cl (90:10), 0.5 mL/min, 25 °C, λ = 250.0 nm]: (R)-1: t R = 29.66 min; (S)-1: t R = 43.35 min. 1H NMR (400 MHz, CDCl3): δ = 7.94 (d, J = 8.84 Hz, 2 H), 7.87 (d, J = 8.16 Hz, 2 H), 7.57 (d, J = 8.92 Hz, 2 H), 7.51 (d, J = 8.44 Hz, 2 H), 7.43 (td, J = 7.5, 1.16, 2 H), 7.29 (td, J = 7.5, 1.18, 2 H), 3.65–3.40 (m, 4 H), 3.11–2.80 (m, 4 H), 0.89 (t, J = 7.08 Hz, 6 H), 0.57 (t, J = 7.08 Hz, 6 H). 13C NMR (100 MHz, CDCl3): δ = 185.15, 149.48, 133.36, 131.50, 128.21, 127.62, 126.97, 126.32, 125.68, 124.09, 123.73, 47.44, 43.40, 12.65, 11.26. HRMS (APCI): m/z [M + H]+ calcd for C30H33N2O2S2: 517.1977; found: 517.1948. Bibenzo[g]chromenediones 3ag; General Procedure An oven-dried 10 mL screw-top tube was charged with (R)-1 (51.7 mg, 0.1 mmol), the appropriate alkyne 2 (0.25 mmol), [Cp*RhCl2]2 (6.2 mg, 0.01 mmol), AgSbF6 (13.7 mg, 0.04 mmol), Cu(OAc)2·H2O (44.0 mg, 0.22 mmol), and CuOAc (24.5 mg, 0.20 mmol). The tube was then filled with N2, and diglyme (2.0 mL) and 1,4-dioxane (2.0 mL) were added from a syringe. The mixture was then heated at 140 °C in an oil bath for 18 h. The resulting mixture was filtered through a pad of Celite, eluting with EtOAc, and the filtrate was concentrated in vacuo. The residue was purified by column chromatography [silica gel, hexane–EtOAc (4:1)] and GPC (CHCl3). The corresponding (S)-isomers were synthesized similarly in small batches for analysis. (R)-3,3′,4,4′-Tetraphenyl-2H,2′H-[10,10′-bibenzo[g]chromene]-2,2′-dione [(R)-3a] White solid; yield: 38 mg (55%); mp >300 °C; [α]D 20 +92.9 [(S)-3a], –94.4 [(R)-3a] (c = 0.1, CHCl3). HPLC [CHIRAL ART Amylose-SA column, hexane–CH3Cl (70:30), 0.2 mL/min, 25 °C, λ = 250.0 nm]: (S)-3a: t R = 27.17 min; (R)-3a: t R = 23.14 min. 1H NMR (400 MHz, CDCl3): δ = 7.14–7.20 (m, 10 H), 7.22–7.24 (m, 2 H), 7.28–7.30 (m, 2 H), 7.35–7.46 (m, 12 H), 7.87 (d, J = 8.2 Hz, 2 H), 7.92 (s, 2 H). 13C NMR (100 MHz, CDCl3): δ = 117.2, 121.0, 125.46, 125.58, 127.65, 127.72, 128.31, 128.47, 128.61, 129.31, 129.53, 129.62, 129.79, 130.59, 134.14, 134.26, 134.77, 148.15, 151.56, 161.01. HRMS (APCI): m/z [M + H]+ Calcd for C50H31O4: 695.2217; found: 695.2211