Zinc-Catalyzed Alkene Cyclopropanation through Zinc Vinyl Carbenoids Generated from Cyclopropenes

The zinc‐catalyzed reaction of cyclopropenes with alkenes leading to vinylcyclopropane derivatives is reported. A broad range of alkenes (including highly substituted or functionalized alkenes) is compatible with this protocol. On the basis of trapping experiments and computational studies, this cyclopropanation reaction is proposed to proceed through initial formation of an electrophilic zinc vinyl carbenoid intermediate, which may be involved in a concerted cyclopropanation reaction. The reported protocol represents an unprecedented and simple strategy for the catalytic generation of zinc vinyl carbenoids, which are promising intermediates in organic synthesis. Open and close! The title reaction provides a convenient and general route to relevant vinylcyclopropane derivatives. Mechanistic studies support the participation of a zinc vinylcarbene intermediate, which may be subsequently involved in a concerted cyclopropanation reaction. This method represents a step towards identifying suitable precursors for the catalytic generation of zinc carbenoids.