Bis(amino)cyclopropenylidenes as Organocatalysts for Acyl Anion and Extended Umpolung Reactions
作者:Myron M. D. Wilde、Michel Gravel
DOI:10.1002/anie.201307167
日期:2013.11.25
Back to BACs: In the pursuit of novel carbene organocatalysts, bis(amino)cyclopropenylidenes (BACs) were explored as alternatives to N‐heterocyclic carbenes. They were effective in catalyzing the Stetter reaction, and displayed unique advantages over the commonly used thiazolylidenes and triazolylidenes. They also mediated extendedumpolungreactions of enals. In addition, chiral analogues can be accessed
Asymmetric intermolecular Stetter reactions catalyzed by a novel triazolium derived N-heterocyclic carbene
作者:Dieter Enders、Jianwei Han、Alexander Henseler
DOI:10.1039/b809913h
日期:——
The asymmetric intermolecular Stetter reaction is catalyzed by a noveltriazoliumsalt derived N-heterocyclic carbene leading to 1,4-diketones in moderate to excellent yields (49-98%) and moderate to good enantioselectivities (56-78% ee), which could be enhanced by one recrystallization to excellent levels (90-99% ee).