SYNTHESE STEREOSELECTIVE DE DIENES CONJUGUES A PARTIR D'ALCOOLS α-ALLENIQUES

Article abstract of DOI:10.1016/S0040-4020(01)88795-0

The reaction of a Grignard reagent with an α-allenic phosphate leads exclusively in every studied case to 1,3-dienes.A high stereoselectivity is observed for the formation of both double bonds; particularly, the organometallic species attacks preferentially in a trans direction from a group located on the terminal allenic carbon.In the case of the esters of secondary alcohols, it is more difficult to determine the factors which govern the stereochemistry of the other double bond.The Z configuration is then favoured in the reaction phosphate + RMgX but the E configuration is predominant in the reaction acetate + R2CuLi.