Illustrated Glossary of Organic Chemistry

Simmons-Smith reaction: A name reaction in which a carbenoid adds to an alkene or alkyne to form a cyclopropane.



Organozinc carbenoid


This Simmons-Smith reaction begins with the halogen-metal exchange between diiodomethane (methylene iodide) and zinc (in a zinc/copper alloy) to produce a reactive intermediate organometallic carbenoid. This carbenoid then undergoes cycloaddition with the pi bond of cyclohexene (an alkene) to produce the cyclopropane ring of bicyclo[4.1.0]heptane.