HIGHLY STEREOSPECIFIC PROCEDURE FOR THE TRANSFORMATION OF ALLYLIC ALCOHOLS INTO 1,3-DIENES

The title synthesis involves (1) epoxidation of allylic alcohols with butyl hydroperoxide in the presence of vanadium catalyst followed by trimethylsilylation, (2) specific oxirane ring opening by means of diethylaluminum 2,2,6,6-tetramethylpiperidide and subsequent desilylation producing 3-ene-l,2-diols5 and (3) removal of both hydroxyl groups through bromination with a mixture of phosphorus tribromide and copper (I) bromide and the successive zinc debromination. The sequence of reactions has been extended with considerable success to the preparations of β-myrcene from nerol, trans-β-ocimene from geraniol in a specific way, and α-and β-famesenes from their biological precursors. A C12 sex pheromone of red bollworm moth has been prepared efficiently by this method with cyclododecene as a starting material.