Thermal and catalytic transylidations between halonium ylides and synthesis and reaction of stable aliphatic chloronium ylides.
Thermal and catalytic transylidations between halonium ylides and synthesis and reaction of stable aliphatic chloronium ylides.
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DOI：
10.1021/ja074624h
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发表时间：
2008-01
影响因子：
15
通讯作者：
M. Ochiai;N. Tada;T. Okada;Atushi Sota;K. Miyamoto
中科院分区：
文献类型：
--
作者：
M. Ochiai;N. Tada;T. Okada;Atushi Sota;K. Miyamoto
开发了卤鎓叶立德之间在热和催化（乙酸铑（II））条件下的分子间转基作用，这使得合成迄今未知的脂肪族氯鎓叶立德以及各种溴鎓叶立德和碘鎓叶立德成为可能。溴到碘鎓叶立德的非催化热转移可能涉及生成活性卡宾：C(SO2CF3)2，其本质上是亲电子的。与溴叶立德和碘叶立德相比，氯叶立德作为生成卡宾（或类胡萝卜素）的更好的前体，并且在非催化热条件下有效地进行烯烃（例如环辛二烯）的环丙烷化。与 λ3-碘基相比，λ3-氯烷基和 λ3-溴酰基具有更大的离去基团能力，这似乎是观察到这些卤鎓叶立德之间反应性差异的原因。
Intermolecular transylidation between halonium ylides under thermal and catalytic (rhodium(II) acetate) conditions, which makes it possible to synthesize a hitherto unknown kind of aliphatic chloronium ylides as well as a variety of bromonium and iodonium ylides, was developed. The uncatalyzed thermal transylidations of bromonium to iodonium ylides probably involve generation of a reactive carbene :C(SO2CF3)2, being electrophilic in nature. Compared to the bromonium and iodonium ylides, the chloronium ylide serves as a much better progenitor for generation of carbenes (or carbenoids) and efficiently undergoes cyclopropanation of olefins such as cyclooctadiene under uncatalyzed thermal conditions. A greater leaving group ability of the λ3-chloranyl and λ3-bromanyl groups compared to that of the λ3-iodanyl group seems to be responsible for the observed differences in reactivity between these halonium ylides.