Novel stereoselective alkenyl–aryl coupling via nickel-catalysed reaction of alkenylanes with aryl halides

trans-Alkenylalanes, readily obtainable via hydroaluminiation of acetylenes, react readily with aryl bromides and iodides in the presence of catalytic amounts of nickel complexes, such as tetrakis(triphenylphosphine)- nickel, to produce arylated alkenes in high yields, the stereochemistry of the products being >99%trans.