in tetrahydrofuran (strict exclusion of air and moisture), Sn complex in THF cooled to -78°C under stirring, treated dropwise under vigorous stirring with C2HMgBr in THF, warmed to room temp., stirred for 12 h; concd.(vac.), suspnd.(hexane), filtered off, washed (hexane) 4 times, evapd., distilled (113°C, 7.5E-3 torr), crystd., elem. anal.;

in THF-d8 (tetrahydrofuran-d8) byproducts: C2H2; (strict exclusion of air and moisture), Sn complex dissolved in toluene-d8, kept at 60°C for 60 h; not isolated, detcd. by NMR;