Noriyuki Yamagiwa

Catalytic asymmetric aldol reaction of ketones and aldehydes using chiral calcium alkoxides

Abstract A chiral hydrobenzoin/Ca complex catalyzes the reaction of acetophenone and aliphatic aldehydes to give the corresponding aldol products in up to 91% ee.

Mixed La–Li heterobimetallic complexes for tertiary nitroaldol resolution

Full details of the kinetic resolution of tertiary nitroaldols derived from simple ketones are described. Mixed BINOL/biphenol La-Li heterobimetallic complexes gave the best selectivity in retro-nitroaldol reactions of racemic tertiary nitroaldols. Using a 2:1 mixture of La-Li 3 -(binaphthoxide 1a) 3 complex (LLB) and La-Li 3 -(biphenoxide 1e) 3 complex, chiral tertiary nitroaldols were obtained in 80-97% ee and 30-47% recovery yield. Transformations of products were also investigated.

Catalytic Asymmetric Epoxidation of α,β‐Unsaturated Phosphane Oxides with a Y(O‐iPr)3/Biphenyldiol Complex

A rare-earth-metal-catalyzed asymmetric epoxidation of alpha,beta-unsaturated phosphane oxides is described. The appropriate selection of a chiral ligand and an achiral additive is important for achieving good reactivity and enantioselectivity. A Y(O-iPr)(3)/biphenyldiol complex with an achiral phosphane oxide additive afforded beta-aryl alpha,beta-epoxy phosphane oxides in 77-99 % yield and with 96-98 % ee. With beta-alkyl substrates, the reaction proceeded smoothly in the absence of an achiral additive, and beta-alkyl alpha,beta-epoxy phosphane oxides were obtained in 94-99 % yield and with 87-95 % ee.