On the basis of the observation that (E)-1-bromo-1-alkenes undergo preferentially stereospecific Pd-catalyzed cross-couplings with a variety of organometallics, in the presence of the corresponding (Z)-stereoisomers, efficient and convenient diastereoselective procedures have been developed to prep. nearly stereoisomerically pure (E)-1-trimethylsilyl-2-alkenes, (E)-1-trimethylsilyl-1-alken-3-ynes (I), (1E, 5E)-1-trimethylsilyl-1,5-alkadien-3-ynes (II), and (1E,3E)-1-trimethylsilyl-1,3-alkadienes (III) from stereoisomeric mixts. of alkenyl bromides.  Compds. I have been stereoselectively converted into (1E,3Z)-1-trimethylsilyl-1,3-dienes (IV) by selective hydrometallations, followed by hydrolysis.  Some synthetic applications of compds. I-IV have been also examd.