[4+2] Cycloaddition of Ketenes with<i>N</i>-Benzoyldiazenes Catalyzed by N-Heterocyclic Carbenes
作者:Xue-Liang Huang、Lin He、Pan-Lin Shao、Song Ye
DOI:10.1002/anie.200804487
日期:2009.1
Enantioselectivity switch: A catalytic enantioselective [4+2] cycloaddition reaction of alkylarylketenes with N‐aryl‐N′‐benzoyldiazenes or N,N′‐dibenzoyldiazenes to give 1,3,4‐oxadiazin‐6‐ones 1 was developed by employing N‐heterocyclic carbene (NHC) catalysts. The enantioselectivities could be switched for most reactions by changing the substituents on the NHC catalyst. TBS=tert‐butyldimethylsilyl