A Practical and Controllable Enantioselective Synthesis of 2-Phenyl-1-cyclopropanecarboxylates via a Camphor-Derived Sulfonium Ylide

Abstract

We have developed a practical and controllable enantio­selective synthesis of 2-phenyl-1-cyclopropane-carboxylates via camphor-derived sulfonium ylide. The procedure has many advantages such as cheap starting materials, facile synthetic procedures, good yields, excellent diastereoselectivities and high enantioselectivities.

enantioselective synthesis - practical method - cyclopropanecarboxylate - sulfonium ylide - diastereoselectivity

References

<A NAME="RU09205ST-1A">1a</A> Li ZN. Liu GS. Zheng Z. Chen H. Tetrahedron  2000,  56:  7187 

<A NAME="RU09205ST-1B">1b</A> Högberg M. Sahlberg C. Engelhardt P. Norèen R. Kangasmetsä J. Johansson NG. Öberg B. Vrang L. Zhang H. Sahlberg BL. Unge T. LÖvgren S. Fridborg K. Bäckbro K. J. Med. Chem.  1999,  42:  4150 

<A NAME="RU09205ST-1C">1c</A> Ikeda T, Kawai A, Mano T, Okumura Y, and Stevens RW. inventors; Japanese Patent 90/323 814  27. 

<A NAME="RU09205ST-1D">1d</A> Lebel H. Marcoux JF. Molinaro C. Charette AB. Chem. Rev.  2003,  103:  971 

<A NAME="RU09205ST-2A">2a</A> Li AH. Dai LX. Aggarwal VK. Chem. Rev.  1997,  97:  2341 

<A NAME="RU09205ST-2B">2b</A> Solladié-Cavallo A. Diep-Vohuule A. Isarno T. Angew. Chem. Int. Ed.  1998,  37:  1689 

<A NAME="RU09205ST-2C">2c</A> Ye S. Huang ZZ. Xia CA. Tang Y. Dai LX. J. Am. Chem. Soc.  2002,  124:  2432 

<A NAME="RU09205ST-3">3</A> Aggarwal VK. Winn CL. Acc. Chem. Res.  2004,  37:  611 

<A NAME="RU09205ST-4">4</A>

4: Mp 103-105 °C. ¹H NMR: δ = 5.77 (s, 1 H), 5.57 (d, J = 16.6 Hz, 1 H), 5.39 (d, J = 16.6 Hz, 1 H), 5.22 (d, J = 7.1 Hz, 1 H), 4.33 (q, J = 7.0 Hz, 2 H), 4.25 (m, 1 H), 3.19 (s, 3 H), 2.04 (d, J = 4.5 Hz, 1 H), 2.03-1.87 (m, 2 H), 1.56-1.50 (m, 2 H), 1.35 (t, J = 7.1 Hz, 3 H), 1.23 (s, 3 H), 1.01 (s, 3 H), 0.87 (s, 3 H). MS (ESI): m/z = 287.1 (M - Br). 5: 4.16-4.14 (m, 1 H), 4.15-3.90 (m, 3 H), 3.85 (d, J = 7.2 Hz, 1 H), 2.96 (s, 1 H), 2.82 (s, 3 H), 1.85-1.81 (m, 3 H), 1.56-1.48 (m, 2 H), 1.26 (t, J = 7.0 Hz, 3 H), 1.21 (s, 3 H), 0.97 (s, 3 H), 0.84 (s, 3 H). 8: Mp 107-109 °C. ¹H NMR: δ = 7.60 -7.27 (m, 5 H), 6.21 (d, J = 7.4 Hz, 1 H), 5.71 (d, J = 12.0 Hz, 1 H), 5.51 (d, J = 12.0 Hz, 1 H), 4.54 (d, J = 7.4 Hz, 1 H), 4.11 (t, J = 7.4 Hz, 1 H), 2.86 (s, 3 H), 1.97 (d, J = 4.5 Hz, 1 H), 1.84-1.80 (m, 1 H), 1.66 (s, 1 H), 1.46-1.29 (m, 2 H), 1.15 (s, 3 H), 0.95 (s, 3 H), 0.81 (s, 3 H). MS (ESI): m/z = 291.1 (M - Br).

<A NAME="RU09205ST-5">5</A>

General procedure for the controllable enantioselective synthesis of 2-phenyl-1-cyclopropanecarboxylates 7c-f via camphor-derived sulfonium ylide 9: To a stirred suspension of sulfonium salt 8 (445 mg, 1.2 mmol) and α,β-unsaturated ester (1.0 mmol) in THF (6 mL) was added t-BuOK (336 mg, 3.0 mmol) or NaH (72 mg, 3.0 mmol) in one portion at the desired temperature (Table [1] ). After stirring for the time indicated (Table [1] ), the reaction mixture was passed through a short silica gel column, which was eluted with ethyl acetate. After concentration of the eluent, the residue was purified by flash column chromatography or preparative TLC, giving 2-phenyl-1-cyclopropanecarboxylate 7c-f.

<A NAME="RU09205ST-6A">6a</A> Johnson CR. Rogers PE. J. Org. Chem.  1973,  38:  1793 

<A NAME="RU09205ST-6B">6b</A> Charett AB. Janes MK. Lebel H. Tetrahedron: Asymmetry  2003,  14:  867 

<A NAME="RU09205ST-6C">6c</A> Li ZN. Zheng Z. Chen HL. Tetrahedron: Asymmetry  2000,  11:  1157 

<A NAME="RU09205ST-6D">6d</A> Doyle MP. Dorow RL. Tamblyn WH. J. Org. Chem.  1982,  47:  4095 

<A NAME="RU09205ST-7A">7a</A> Inouye Y. Sugita T. Walborsky HM. Tetrahedron  1964,  20:  1695 

<A NAME="RU09205ST-7B">7b</A> Evans DA. Woerpel KA. Scott MJ. Angew. Chem. Int. Ed.  1992,  31:  430