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-la equivalent is reported by bromine-magnesium exchange reaction of the 3bromo-4-(dimethylamino)pyridine (2). The chiral sulfoxide appendage is introduced by trapping the resulting Grignard intermediate with (lR,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.