Regio- and stereoselective installation of alkyl groups onto cis 4-cyclopentene-1,3-diol monoacetate by using reagents derived from alkylmagnesium halides

Reaction of cis 4-cyclopentene-1,3-diol monoacetate with alkyl reagents derived from RMgX and CuCN furnished either trans 4-alkyl-2-cyclopenten-1-ols (1,4-isomers) or trans 2-alkyl-3-cyclopenten-1-ols (1,2-isomers) depending upon the stoichiometry of RMgX/CuCN and the solvents used (Et2O or THF).