equimolar amt. of educt, t-BuOH dropped to B(NEt2)2Sn(CH3)3 at -30°C, stirred;

B(N(C2H5)2)2Sn(CH3)3 dropped to Sn(CH3)3Li at 0°C for 2 h, stirred for 4 h; evapd., dissolved in Et2O, filtered, distd., elem.anal.;