AN EFFICIENT AND HIGHLY STEREOSELECTIVE SYNTHESIS OF TRIMETHYLSILYLVINYLCYCLOPROPANE DERIVATIVES VIA AN ORGANOTELLURONIUM SALT - FIRST EXAMPLE OF CATALYTIC WITTIG-TYPE CYCLOPROPANATION

A one-pot reaction of 3-trimethylsilylprop-2-enyl(diisobutyl)telluronium bromide 1 with alpha,beta-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 alpha,beta-unsaturated ketones in the presence of caesium carbonate.