Synthesis of Novel Phenylnaphthyl Phosphines and their Applications to Pd-Catalyzed Intramolecular Amidation

Abstract

Novel phenylnaphthyl phosphines were prepared and ­applied to the Pd-catalyzed intramolecular amidation. Both ligands gave good to excellent yields in the synthesis of five-, six-, and ­seven-membered rings from halo-amides and carbamates.

phenylnaphthyl phosphine - Pd catalysis - C-N bond formation - intramolecular amidation - Suzuki-Miyaura cross-coupling

References and Notes

For reviews on transition-metal catalyzed carbon-heteroatom bond formations, see:

1a Prim D. Andrioletti B. Rose-Munch F. Rose E. Couty F. Tetrahedron  2004,  60:  3325 

1b Ley SV. Thomas AW. Angew. Chem. Int. Ed.  2003,  42:  5400 

1c Prim D. Campagne J.-M. Joseph D. Andrioletti B. Tetrahedron  2002,  58:  2041 

1d Muci AR. Buchwald SL. Top. Curr. Chem.  2002,  219:  131 

1e Yang BH. Buchwald SL. J. Organomet. Chem.  1999,  576:  125 

1f Wolfe JP. Wagaw S. Marcoux J.-F. Buchwald SL. Acc. Chem. Res.  1998,  31:  805 

1g Hartwig JF. Angew. Chem. Int. Ed.  1998,  37:  2046 

1h Hartwig JF. Synlett  1997,  329 

2a He F. Foxman BM. Snider BB. J. Am. Chem. Soc.  1998,  120:  6417 

2b Morita S. Kitano K. Matsubara J. Ohtani T. Kawano Y. Otsubo K. Uchida M. Tetrahedron  1998,  54:  4811 

3a Beccalli EM. Broggini G. Paladino G. Zoni C. Tetrahedron  2005,  61:  61 

3b Ferreira ICFR. Queiroz M.-JRP. Kirsch G. Tetrahedron  2002,  58:  7943 

3c López-Rodríguez ML. Benhamú B. Ayala D. Rominguera JL. Murcia M. Ramos JA. Viso A. Tetrahedron  2000,  56:  3245 

4a Wolfe JP. Tomori H. Sadighi JP. Yin J. Buchwald SL. J. Org. Chem.  2000,  65:  1158 

4b Old DW. Wolfe JP. Buchwald SL. J. Am. Chem. Soc.  1998,  120:  9722 

5 For a review on BINAP, see: Noyori R. Takaya H. Acc. Chem. Res.  1990,  23:  345 

6 For a review on MOP, see: Hayashi T. Acc. Chem. Res.  2000,  33:  354 

7 Yoshikawa S. Odaira J. Kitamura Y. Bedekar AV. Furuta T. Tanaka K. Tetrahedron  2004,  60:  2225 

Our group has used the structurally related optically active 8,8′-disubstituted 1,1′-binaphthyls as chiral modifiers. For examples, see:

8a Fuji K. Ohnishi H. Moriyama S. Tanaka K. Kawabata T. Tsubaki K. Synlett  2000,  351 

8b Tanaka K. Nuruzzaman M. Yoshida M. Asakawa N. Yang X.-S. Tsubaki K. Fuji K. Chem. Pharm. Bull.  1999,  47:  1053 

8c Fuji K. Yang X.-S. Ohnishi H. Hao X.-J. Obata Y. Tanaka K. Tetrahedron: Asymmetry  1999,  10:  3243 

8d Tanaka K. Asakawa N. Nuruzzaman M. Fuji K. Tetrahedron: Asymmetry  1997,  8:  3637 

9

The ligand 6 could be purified by column chromatography under atmospheric conditions. Spectral data of 6: ¹H NMR: δ = 3.37 (s, 3 H), 6.67-6.65 (m, 1 H), 6.86 (dd, J = 0.8, 7.0 Hz, 1 H), 7.16-7.11 (m, 5 H), 7.27-7.21 (m, 9 H), 7.37-7.31 (m, 2 H), 7.74-7.44 (m, 1 H), 7.74 (dd, J = 0.8, 8.0 Hz, 1 H). MS (FAB): m/z = 419 (M + H)⁺. HRMS: m/z calcd for C₂₉H₂₄OP (M + H)⁺, 419.1564; found, 419.1531.

For reviews on the Suzuki-Miyaura cross-coupling, see:

10a Suzuki A. J. Organomet. Chem.  1999,  576:  147 

10b Miyaura N. Suzuki A. Chem. Rev.  1995,  95:  2457 

11

Spectral data of 11: ¹H NMR: δ = 3.48 (s, 3 H), 6.65-6.60 (m, 1 H), 6.83-6.70 (m, 4 H), 7.30-7.00 (m, 13 H), 7.50-7.45 (m, 1 H), 7.88 (d, J = 7.9 Hz, 2 H). MS (FAB): m/z = 419 (M + H)⁺. HRMS: m/z calcd for C₂₉H₂₄OP (M + H)⁺, 419.1564; found, 419.1524.

12a Yang BH. Buchwald SL. Org. Lett.  1999,  1:  35 

12b Wolfe JP. Rennels RA. Buchwald SL. Tetrahedron  1996,  52:  7525 

13

Intramolecular Amidations; General Procedure To a mixture of 6 (9.8 mg, 23 µmol) and Pd(OAc)₂ (6.3 mg, 28 µmol) in 1,4-dioxane (3.0 mL) was added 12 (142 mg, 0.47 mmol) and Cs₂CO₃ (228 mg, 0.70 mmol) at r.t. The reaction was stirred at 100 °C for 3.5 h, EtOAc and H₂O were added, and the resulting mixture was filtered through a pad of Celite. The organic layer was separated, washed with brine, dried over MgSO₄, and then evaporated to give a residue, which was purified by column chromatography (SiO₂; hexane-EtOAc, 3:2) to afford 13 (88 mg, 85%).

14

In a previous report, the cyclization of 12 was conducted with Pd(OAc)₂ (3.3 mol%), (dl)-MOP (5.0 mol%), and K₂CO₃ (1.4 equiv) in toluene at 100 °C for 36 h to give 13 in 82%; see, ref. 12a.

15a Baillie C. Xiao J. Tetrahedron  2004,  60:  4159 

15b Baillie C. Chen W. Xiao J. Tetrahedron Lett.  2001,  42:  9085 

16

The starting material 12 was recovered in 72% yield. No reductive dehalogenation of 12 as a side reaction was observed.

Both η ¹- and η ²-coordinations of arenes to Pd(0) were previously proposed as plausible explanations for the excellent properties of electron-rich biaryl phosphines:

17a For η ¹-coordination, see: Reid SM. Boyle RC. Mague JT. Fink MJ. J. Am. Chem. Soc.  2003,  125:  7816 

17b For η ²-coordination, see: Yin J. Rainka MP. Zhang X.-X. Buchwald SL. J. Am. Chem. Soc.  2002,  124:  1162 

18

Attempts to synthesize the eight-, nine-, and ten-membered lactams using 23, 24, and 25 as the starting materials, respectively, were unsuccessful (Figure [2] ).
In every case only the starting materials were recovered.