A detailed mechanistic study of the Z-selective allylic functionalization via thianthrenium salts is presented. Kinetic analyses, deuterium labeling experiments, and computational methods are used to rationalize the observed reactivity and selectivity. We find that the reaction proceeds via a rate-determining and stereodetermining allylic deprotonation of an alkenylthianthrenium species. The Z-configuration of the resultant allylic ylide is translated into the Z-allylic amine product through a sequence of subsequent fast and irreversible steps: protonation to form a Z-allylic thianthrenium electrophile and then regioselective substitution by the nucleophile. In the stereodetermining deprotonation step, computational studies identified a series of stabilizing nonbonding interactions in the Z-alkene-forming transition state that contribute to the stereoselectivity.

中文翻译：

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通过铊盐进行 Z 选择性烯丙基官能化的机制


提出了通过铊盐进行 Z 选择性烯丙基官能化的详细机制研究。动力学分析、氘标记实验和计算方法用于合理化观察到的反应性和选择性。我们发现该反应通过烯基噻蒽鎓物种的速率决定和立体决定烯丙基去质子化进行。所得烯丙基叶立德的 Z 构型通过一系列后续快速且不可逆的步骤转化为 Z-烯丙基胺产物：质子化形成 Z-烯丙基铊亲电子试剂，然后被亲核试剂进行区域选择性取代。在立体决定去质子化步骤中，计算研究确定了 Z-烯烃形成过渡态中的一系列稳定非键相互作用，这些相互作用有助于立体选择性。