In the presence of catalytic amounts of
Pd
2
(dba)
3
·CHCl
3
and dppb, the
reaction of pronucleophiles 1 with vinyltins 2 gives the corresponding
alkylative dimerization products of the vinyl group, 1,4-disubstituted
butene derivatives 3, in good to high yields.
(CH3)2Sn(CHCH2)2·2 CuCl, and (C4H9)Sn(CHCH2)2·2 CuCl are prepared by allowing the neat vinylmetallic to react with copper(I) chloride. The new π-complexes are characterized by elemental analysis and by IR and NMR spectroscopy. A bonding schme is proposed to explain the unusual liability of these complexes.