n-butyllithium in tetrahydrofuran; hexane; 2-methyl cyclohexane under N2, n-BuLi in hexane/methylcyclohexane treated at -78°C with THF, equiv. amt. of heterocycle in THF added dropwise with stirring, kept overnight over dry ice, soln. of Me3SnCl in THF added dropwise, allowed to warm to room temp.; concd. in vac., methylcyclohexane added, filtered, fractionally distd.;elem. anal.;