Highly versatile enantioselective conjugate addition of Grignard reagents to alpha,beta-unsaturated thioesters

作者：Ruiz Beatriz Macia; Geurts Koen; Fernandez Ibanez M Angeles; ter Horst Bjorn; Minnaard Adriaan J; Feringa Ben L^*

来源：Organic Letters, 2007, 9(24): 5123-5126.

DOI：10.1021/ol702425a

Herein, we report efficient catalysts for the asymmetric copper-catalyzed conjugate addition of Grignard reagents to alpha,beta-unsaturated thioesters. MeMgBr Adds to aromatic ocfl-u nsatu rated thioesters with excellent enantioselectivities and moderate to good yields using Josiphos/CuBr and Tol-BINAP/Cul complexes. The use of bulky Grignard reagents leads to unprecedented enantioselectivities in the 1,4-addition to a broad range of aromatic and aliphatic alpha,beta-unsaturated thioesters using Tol-BINAP/Cul. The highest enantioselectivities reported so far for the addition of Grignard reagents to crowded beta-substituted aliphatic substrates are achieved with Tol-BINAP/Cul.

• 出版日期2007-11-22