Protected <i>syn</i>-Aldol Compounds from Direct, Catalytic, and Enantioselective Reactions of <i>N</i>-Acyl-1,3-oxazinane-2-thiones with Aromatic Acetals

Abstract

A direct and asymmetric <i>syn</i>-aldol reaction of <i>N</i>-acyl-1,3-oxazinane-2-thiones with dialkyl acetals from aromatic acetals in the presence of 2-5 mol % [DTBM-SEGPHOS]NiCl₂, TMSOTf, and lutidine has been developed. It has been established that the oxazinanethione heterocycle, used for the first time as a scaffold in asymmetric carbon-carbon bond-forming reactions, can be smoothly removed to give access to a variety of enantiomerically pure compounds with high synthetic value.