Highly Enantioselective Simmons–Smith Fluorocyclopropanation of Allylic Alcohols via the Halogen Scrambling Strategy of Zinc Carbenoids

Highly
enantio- and diastereoenriched monofluorocyclopropanes were
accessed via the Simmons–Smith fluorocyclopropanation of allylic
alcohols using difluoroiodomethane and ethylzinc iodide as the substituted
carbenoid precursors. The scrambling of halogens at the zinc carbenoid
led to the formation of the fluorocyclopropanating agent (fluoroiodomethyl)­zinc­(II)
fluoride. This strategy circumvented the ongoing limitation in Simmons–Smith
fluorocyclopropanations relying on the use of the relatively inaccessible
and expensive carbenoid precursor fluorodiiodomethane.