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.
报道了一种通过3-溴-4-(二甲基
氨基)
吡啶(2)的
溴-
镁交换反应,一步合成了新的手性
DMAP-1a类似物。通过与(1R,2S,5R)-(-)-(S)-薄荷基对
甲苯亚砜酸盐捕获生成的格氏中间体,引入了手性亚砜片段,以60%的产率和高度光学纯度得到了(S)-1a。初步评价1a作为亲核催化剂的效果表明,在各种醇的酰化动力学拆分过程中表现出有希望的选择性(s = 4.5)。