The representative (E)-1-alkenyldisiamylboranes and (E)-1-alkenyl-1,3,2-benzodioxaboroles readily obtainable Image hydroboration of 1-alkynes react with 1-alkenyl halides or 1-alkynyl halides in the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium and base to give corresponding conjugated (E)-dienes or (E)-enynes with high regio- and stereospecificity in good yields, respectively.