Direct and enantioselective aldol reactions catalyzed by chiral nickel(II) complexes

Abstract

A direct and asymmetric aldol reaction of N-acylthiazinanethiones with aromatic aldehydes catalyzed by chiralnickel(II) complexes is reported. The reaction gives thecorresponding O-TIPS-protected anti-aldol adducts in highyields and with remarkable stereocontrol and atom economy.Furthermore, the straightforward removal of the achiralscaffold provides enantiomerically pure intermediates ofsynthetic interest, which involve precursors for anti-a-amino-b-hydroxy anda,b-dihydroxy carboxylic derivatives. Theoret-ical calculations explain the observed high stereocontrol.