tetrakis(triphenylphosphine) palladium(0) in not given to soln. of alkyne added ((n-Bu)3Sn)2Zn and 5 molpercent catalyst, then treated with H3O(1+) at 0 °C for 10 min; ratio of C10H21C(SnBu3)CH2 : (C10H21)CHCH(SnBu3) >95:<5; combined yield - 70percent;