A One-Pot Preparation of Allylsilanes and (Z)-Alk-2-enylsilanes

Metalation of 1-alkenes with a mixt. of BuLi and KOCMe3 in tetrahydropyran, followed by stereochem. equilibration and treatment with Me3SiCl, afforded (2-alkenyl)trimethylsilanes in good yield and with Z:E ratios of 95:5 to 98:2. E.g., reaction of RCH2CH:CH2 (R = Pr, Bu, pentyl, hexyl, heptyl, octyl, nonyl) as above gave 52-75% Z-RCH:CHCH2SiMe3. Deprotonation of propene was rapidly and readily accomplished with a stoichiometric amt. of the superbase suspended in pentane on a 1 mol scale. [on SciFinder (R)]