CO<sub>2</sub>on a Tightrope: Stabilization, Room-Temperature Decarboxylation, and Sodium-Induced Carboxylate Migration
作者:Achim Häußermann、Frank Rominger、Bernd F. Straub
DOI:10.1002/chem.201202298
日期:2012.10.29
carbanionic intermediate. Corresponding spiro compounds containing silylene and stannylene moieties show high thermal stability. Addition of an excess of methyllithium to the sodium salt triggers a reaction sequence comprising a deprotonation, carboxylate transfer, and nucleophilic trapping of the rearranged carboxylate by another equivalent of methyllithium. Hydrolytic work‐up of the geminal diolate leads
通过吲哚的连续化学选择性双烷基化反应合成了具有空间屏蔽作用的3-取代的两性离子N,N-二甲基异胰二铵羧酸盐。在室温下,羧酸盐会在二甲基亚砜(DMSO)或二甲基甲酰胺(DMF)中进行定量且异常容易的脱羧。溶剂分子破坏几乎等距的氢键会引发杂化CC裂解。脱羧速率随CO 2的增加而降低分压,证明了碳负离子中间体的质子化和再羧化的竞争力。相应的含有亚甲硅烷基和亚锡亚烷基部分的螺环化合物显示出高的热稳定性。向钠盐中添加过量的甲基锂会触发反应序列,该反应序列包括去质子化,羧酸盐转移以及另一等价的甲基锂对重排的羧酸盐的亲核捕获。对双羟甲基双羟乙酸酯进行水解后可得到乙酰基产物。氘代实验尚未阐明钠抗衡离子的作用和重排的机理。