in cyclohexane Irradiation (UV/VIS); Ar-atmosphere; high pressure Hg lamp;

methyllithium in tetrahydrofuran; diethyl ether under N2 or Ar, dropwise addn. of MeLi in THF/Et2O to Si(SnMe3)4 in THF , stirred for 22 h; removal of volatiles, extn. (pentane), concd., cooled to -40°C, filtered, dried (four crops);