Propargylic epoxides easily react with Grignard reagents and catalytic amounts of copper(I) salt to afford a-allenic alcohols. The reaction is highly diastereoselective and its stereochemical outcome (syn or anti isomer) can be fully controlled. The syn diastereomer, probably arising through an addition-elimination mechanism, is better obtained with RMgCl and copper(I) bromide, whereas the anti diastereomer, is better obtained with RMgBr and a complexed copper(I) salt. With RLi and a catalytic amount of copper salt, phenethynyl cyclohexene oxide reacts through reductive lithition, affording, stereoselectivety, an allenyl lithium reagent.