Halogenated Donor–Acceptor Cyclopropanes as Donor–Acceptor Cyclopropene Surrogates

Herein we report (3+2)-cycloaddition reactions of halogenated donor-acceptor cyclopropanes (HDACs) as surrogates for donor-acceptor cyclopropenes. Upon reaction with a variety of 2π-components, cycloaddition followed by elimination generates the unsaturated five-membered ring products. A series of HDACs were shown to be effective in reactions with thioketones. Five further cycloaddition reactions were used to showcase the broad applicability of these donor-acceptor cyclopropene surrogates. Kinetic studies allowed the proposal of a plausible mechanism for this reaction.