Synthesis of (Z)-Vinylsilanes with High Diastereoselectivity by Using Samarium Diiodide
摘要:
[GRAPHICS]Beta-Elimination of O-acetyl 1-chloro-1-trimethylsilylalkan-2-ols 1 was achieved by using samarium diiodide as a metaling reagent and afforded the corresponding (Z)-vinylsilanes with high stereoselectivity. The starting compounds 1 were easily prepared by treatment of different aldehydes with (chlorolithiomethyl)trimethylsilane and further acetylation.
(Diiodomethyl)trimethylsilane (Me3SiCHI2, 1) is produced by treatment of iodoform with manganese in the presence of Me3SiCl. Aldehydes are converted to (E)-1-trimethylsilyl-1-alkenes in a stereosel...
One-Pot Transformation of RCHO to (<i>E</i>)-RCH=CHSiMe<sub>3</sub> Using CHI<sub>3</sub>, Mn, Me<sub>3</sub>SiCl, and a Catalytic Amount of CrCl<sub>2</sub>
Iodoform is reduced with manganese in the presence of Me3SiCl to give Me3SiCHI2 (1). A one-pot transformation of aldehydes to (E)-1-alkenyltrimethylsilanes is then performed with iodoform, manganese, Me3SiCl, and a catalytic amount of chromium(II) chloride in THF via in situ formation of 1.
Aldehydes are converted to the corresponding (E)-alkenylsilanes with one carbon homologation by means of a gemdichromium reagent prepared by CrCl2 reduction of Me3SiCHBr2 in THF. Transformation of aldehydes into alkenyl sulfides is also achieved with a combination of PhSCHCl2 and CrCl2.