Regioselective Route to Sterically Hindered Cyclopropylcarbinyl Halides

Article abstract of DOI:10.1021/jo00177a008

Reaction of cyclopropylcarbinyl alcohols 1 with hexachloroacetone and triphenylphosphine resulted in 80 - 90 percent yields of the corresponding cyclopropylcarbinyl chlorides 4 regioselectively, with no trace of the homoallylic chloride 2 or the chlorocyclobutane derivative 6a.Similar reaction of 1 with bromine and triphenylphosphine, in dimethylformamide, gave 65 - 80 percent yields of the cyclopropylcarbinyl bromide 5 with trace amounts of the homoallylic bromide 3 but no detectable bromocyclobutane derivative 6b.These reactions are amenable to the preparation of very sterically hindered cyclopropylcarbonyl halides, heretofore inaccessible, regioselectively and in a facile manner.