tetrakis(triphenylphosphine) palladium(0) in benzene T=100°C; 18 h;

boron trifluoride diethyl etherate; copper (I) cyanide in diethyl ether under Ar; soln. of MeLi (3 equiv.) added dropwise at -30°C to stirred suspn. of CuCN (3 equiv.) in anhyd. ether (30 min); cooled to -78°C; BF3*OEt2 (3 equiv.) added; stirred for 30 min; Sn compd. (1 equiv.) in ether added; stirred for 3 h; warmed to -50°C; hydrolysed with aq. NaHCO3 soln.; extd. with ether; chromd. (alumina); mixt. of Z and E isomers (80:20) obtained, total yield 81percent;