lithium diisopropyl amide; methyl iodide in tetrahydrofuran; hexane treating a THF/hexane soln. of i-Pr2NLi with an equimol. amt. of the stannane at low temp., addn. of CH3I;

n-butyllithium; water; diisopropylamine in tetrahydrofuran; hexane; Petroleum ether N2-atmosphere; stirring (0°C, 15 min), Sn-compd. addn. (-70°C), stirring (-50°C, 30 min), MeI addn., petroleum ether addn. (0°C), H2O addn.; extg. (petroleum ether), washing (H2O), drying (MgSO4), evapn., distg.; elem. anal.;