in toluene 5 h at 70°C.; evapn. under vac., extn. with n-pentane, washing, sublimation (80-100°C, 5 mtorr), elem. anal.;

in cyclohexane byproducts: C6H5CCH; 16 h at 60°C;

in ethylene glycol dimethyl ether; isopropyl alcohol byproducts: NaCl; absence of moisture; dropwise addn. of BuSnCl3 to 3 equiv. of alkoxide (in i-PrOH/DME=1:2 v/v), refluxing for 3 h; filtration off of NaCl, evapn. (reduced pressure), distn. (vac.);