Single-step preparation of a 4-(dimethylamino)pyridine analogue bearing a sulfoxide as new chiral inducer.: Preliminary evaluation as nucleophilic catalyst

A one-step synthesis of a new chiral DMAP-1a equivalent is reported by bromine-magnesium exchange reaction of the 3-bromo-4-(dimethylamino)pyridine (2). The chiral sulfoxide appendage is introduced by trapping the resulting Grignard intermediate with (1R,2S,5R)-(-)-(S)-menthyl p-toluenesulfinate affording (S)-1a in 60% yield and high optical purity. A preliminary evaluation of la as nucleophilic catalyst has demonstrated promising selectivity (s = 4.5) during acylative kinetic resolution of various alcohols.