Direct and Enantioselective Aldol Reactions Catalyzed by Chiral Nickel(II) Complexes

摘要

A direct and asymmetric aldol reaction of N-acyl thiazinanethiones with aromatic aldehydes catalyzed by chiral nickel(II) complexes is reported. The reaction gives the corresponding O-TIPS-protected anti-aldol adducts in high yields and with remarkable stereocontrol and atom economy. Furthermore, the straightforward removal of the achiral scaffold provides enantiomerically pure intermediates of synthetic interest, which involve precursors for anti-alpha-amino-beta-hydroxy and alpha,beta-dihydroxy carboxylic derivatives. Theoretical calculations explain the observed high stereocontrol.