The Grignard reagent 6, in which the magnesium-bearing carbon
atom is the sole stereogenic centre has been added to CO2,
PhNCO, PhNCS and certain aldehydes with full retention of configuration.
Reaction with benzophenone, electron-deficient aldehydes and several allyl
halides proceeded with partial or complete racemization. The findings are
discussed with respect to a dichotomy between concerted polar and stepwise
SET reaction pathways.
格氏试剂 6 中的含
镁碳原子是唯一的立体中心,该试剂已加入
CO2、PhNCO、Ph
NCS 和某些醛中,并完全保留了构型。
与
二苯甲酮、缺电子醛和几种烯丙基卤化物反应时,会发生部分或完全消旋化。这些发现与协同极性反应途径和逐步
SET 反应途径之间的二分法有关。