A highly diastereoselective synthesis of (E)-B-2-(1-cyclopropyl-1-alkenyl)-1, 3, 2-dioxaborinanes. Isolation and oxidation to alkyl cyclopropyl ketones
A convenient, novel synthesis of alkyl cyclopropyl ketones based on Z-1-bromo-1- alkenylboronate esters is developed. α-Bromo-(Z)-1-alkenylboronate esters readily available from literature procedures smoothly undergo a reaction with cyclopropylmagnesium bromide in tetrahydrofuran to provide the corresponding 'ate'complexes. These 'ate'complexes undergo intramolecular nucleophilic substitution ...