in tetrahydrofuran byproducts: C2H4; all manipulations under Ar; slow addn. of the acetylene derivative to a soln. of (PPh3)2Ni(C2H4) at room temp., stirring at 25°C for 0.5 h, heating at 40-50°C until the evolution of gas stopped; filtration, addn. of n-hexane, crystn. on cooling to -40°C or -78°C for 2-5 d), the ppt. was filtered off, washed with cold n-hexane twice, and dried under vac.; elem. anal.;

Na/Hg (10percent) in not given N2 atmosphere; excess of Na-amalgam; filtration, solvent evapn., extn. (pentane), crystn.;