BuLi in diethyl ether BuLi added to soln. of ligand in Et2O at -80°C; after 2 h soln. of Bu3SnCl in Et2O (dissolved at -80°C) added slowly at -110°C; warmed to room temp. overnight; hexane added; filtered; solvent removed on rotary evaporator; distd. in vac. (242°C, 0.2 mmHg); elem. anal.;