An efficient and highly stereoselective synthesis of trimethylsilylvinylcyclopropane derivatives via an organotelluronium salt: first example of catalytic Wittig-type cyclopropanation
Abstract
A one-pot reaction of 3-trimethylsilylprop-2-enyl(diisobutyl)telluronium bromide 1 with α,β-unsaturated ketones gives, by way of Michael addition in the presence of caesium carbonate under solid–liquid phase-transfer conditions, trimethylsilylvinylcyclopropanes both in high to excellent yields and with high stereoselectivity. A similar high-yielding cyclopropanation occurs in THF/trace of water with diisobutyl telluride as catalyst in a one-pot reaction of (E)-3-bromo-1-trimethylsilylprop-1-ene with α,β-unsaturated ketones in the presence of caesium carbonate.