Potassium Organotrifluoroborates in Rhodium-Catalyzed Asymmetric 1,4-Additions to Enones

Abstract

Potassium organotrifluoroborates, highly stable organoboron derivatives, participate in asymmetric 1,4-additions to enones. This reaction, catalyzed by cationic rhodium(I) complexes chelated with binap, MeO-biphep or josiphos ligand, affords 1,4-adducts with high yields and enantioselectivities of up to 99%. Careful study of the reaction parameters shows the high sensitivity of the reaction to temperature, solvent and the amount of water cosolvent. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)