from α-substituted (homo)allyl alcohols. In tandem reactions, cyclopropyl carbinols are obtained from allyloxylithium or -magnesium intermediates, generated in situ by alkylation of conjugated aldehydes, ketones, and esters as well as from allyl esters and carbonates or vinyloxiranes. [¹] cyclopropanation - Barbier conditions - Grignard addition - alkyllithiumaddition - dibromomethane
A method for the preparation of cyclopropyl carbinols by cyclopropanation of unsaturated alcoholates, utilising a reagent system selected from (A) magnesium metal and dibromomethane, and (B) dibromomethane and a tertiary Grignard reagent, the reaction being carried out in the presence of an ether solvent.
The process is useful, for example, for the preparation of ingredients for the flavour and fragrance industry.
In tandem reactions, cyclopropylcarbinols are obtained from allyloxylithium or -magnesium intermediates, generated in situ by alkylation of conjugated aldehydes, ketones, and esters as well as from allyl carboxylates or vinyloxiranes. Using this methodology, numerous fragrance ingredients and their precursors were efficiently converted to the corresponding cyclopropylcarbinols.