1,1-Dihalogenocyclopropanes derived from terpenes. The stereochemistry of cyclopropylidene insertion into carbon–hydrogen bonds adjacent to alcohols

Abstract

Treatment of the alcohol (13) with methyl-lithium in ether leads to the ketone (5), whereas (12) gives no ketone and the major product is the alcohol (16). The formation of (5) from (13) establishes the requirement for a syn-relationship between a C–H bond at the 1-position and C-2′ in the conversion of 1-(2′,2′-dibromocyclopropyl)alkan-1-ols into (cyclopropyl)alkyl ketones.