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Chemoselective and stereoselective lithium carbenoid mediated cyclopropanation of acyclic allylic alcohols
M J Durán-Peña1, M E Flores-Giubi1, J M Botubol-Ares1
1Departamento de Química Orgánica, Facultad de Ciencias, Campus Universitario Puerto Real s/n, Torre sur, 4° planta. and Universidad de Cádiz, 11510, Puerto Real, Cádiz, Spain. rosario.hernandez@uca.es antoniojose.macias@uca.es.
Abstract:
The reaction of geraniol with different lithium carbenoids generated from n-BuLi and the corresponding dihaloalkane has been evaluated. The reaction occurs in a chemo and stereoselective manner, which is consistent with a directing effect from the oxygen of the allylic moiety. Furthermore, a set of polyenes containing allylic hydroxyl or ether groups were chemoselectively and stereoselectively converted into the corresponding gem-dimethylcyclopropanes in one single step in moderate to good yields mediated by a lithium carbenoid generated in situ by the reaction of n-BuLi and 2,2-dibromopropane.
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