in dichloromethane (N2); to soln. of B compd. was dropped soln. of Sn compd. within 20 minat -10°C; mixt. was sepd. by fractionated distn. in vac.; elem. anal.;

in dichloromethane (N2); into soln. of B compd. was dropped soln. of Sn compd. within 20 min at -10°C; mixt. was sepd. by fractionated distn. in vac., yielding mixt. of B compds. and sepd. Et3SnCl;

in dichloromethane (N2); into soln. of B compd. was dropped soln. of Sn compd. within 20 min at -10°C; mixt. was sepd. by fractionated distn. in vac., yielding mixt. of B compds. and sepd. Et3SnCl;