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 1a as nucleophilic catalyst has demonstrated promising selectivity (s = 4.5) during acylative kinetic resolution of various alcohols.