methyllithium in not given byproducts: CH3OCH2OCH2Li; Sn-compd. was reacted with MeLi in THF or DME at -60°C for 10 min; equil. react.; analysed by (1)H and (13)C NMR spectra;

in tetrahydrofuran Ar; butyltin-compound dissolved in THF cooled to -40 °C; LiBu added; stirred 15 min at -40 °C; Me3SnCl in THF was added; stirring 10 min;; poured into NH4Cl-soln. and petroleum ether; organic layer was separated, washed (brine); dried (Na2SO4); filtered; concd.; preparative TLC (ethyl acetate/petroleum ether 0.5:99.5);;