Abstract In the stereospecific palladium-catalysed cross-coupling reaction of 1-alkynylzinc chlorides or (E)-1-alkenyl diisobutylalanes,(E)-2-bromovinyltrimethylsilane reacts preferentially, in the presence of the corresponding (Z)-stereoisomer to afford good yields of (E)-1-trimethylsilyl-1-en-3-ynes (4) or (1E, 3E)-1-trimethylsilyl-1, 3-dienes (6), respectively, having very high stereoisomeric purities. Compounds 4 are easily converted into (1E, 3Z)- ...