Intramolecular cyclization and subsequent rearrangements of alkyne-tethered N-heterocyclic carbenes
作者:Marc C.B. Legault、Craig S. McKay、Joseph Moran、Matthew A. Lafreniere、John Paul Pezacki
DOI:10.1016/j.tetlet.2012.08.038
日期:2012.10
imidazole and 1,2,4-triazole-based N-heterocyclic carbene precursors have been prepared and studies of the intramolecular reactions of carbenes are performed. Products consistent with intramolecular cyclizations and subsequent rearrangements were observed. Mechanistic studies using crossover experiments showed that the products did arise from intramolecular carbene additions. The reactions are proposed
炔烃系咪唑和1,2,4-三唑基N-杂环卡宾前体已经制备,并进行了卡宾分子内反应的研究。观察到与分子内环化和随后的重排一致的产物。使用交叉实验的机理研究表明,产物的确来自分子内卡宾的添加。提议该反应通过类似于Boger环加成反应中形成的乙烯基二烷氧基卡宾的乙烯基二氨基卡宾中间体。观察到咪唑取代的二烯是串联环化和消除反应的主要产物,对于基于咪唑的N-杂环卡宾来说,这是观察到的。