N-Heterocyclic carbene–palladium catalysts are used to promote addition/ring opening of cyclopropenones with terminal alkynes. The ring-opening alkynylation affords alkenyl alkynyl ketones in good yields. For reactions with propargylic esters having an aryl or alkenyl substituent at the propargylic position, [3+2] annulation occurs exclusively to give 4-methylenecyclopentenones.
N-杂环卡宾-
钯催化剂用于促进
环丙烯酮与末端
炔烃的加成/开环。开环炔基化以良好的产率提供烯基炔基酮。对于与在炔丙基位置具有芳基或烯基取代基的炔丙基酯的反应,[3+2]环化仅发生以产生4-亚甲基
环戊烯酮。