stereochemical integrity. Overall the reaction sequence is a resolution but without the need for an acidic or basic substituent—a ‘traceless’ method. In certain instances, for example when the nucleophile is an ortholithiated peri-substituted 1-naphthamide, the diastereoisomeric sulfoxides may be interconverted thermally. This allows a dynamic resolution, under thermodynamic control, and hence in principle
(-)-薄荷基亚
磺酸盐与阻转异构但外消旋的芳基
锂反应生成两种阻转非对映异构亚砜。每种非对映异构体的分离(通过色谱法或结晶法)和亚砜-
锂交换可再生出对映体纯形式的芳基
锂,可以用一系列亲电试剂将其淬灭,并保留立体
化学完整性。总的来说,反应顺序是分离的,但不需要酸性或碱性取代基-“无痕”方法。在某些情况下,例如,当亲核试剂为ortholithiated迫取代的1-
萘酰胺可以将非对映异构亚砜热转化。这允许在热力学控制下进行动态拆分,因此原则上可以使最终产物的产率大于50%。通过合成已知的阻转异构
膦配体证明了该方法的实用性。