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)telluroni um bromide 1 with alpha,beta-unsaturated ketones gives, by way of Mich ael addition in the presence of caesium carbonate under solid-liquid p hase-transfer conditions, trimethylsilylvinylcyclopropanes both in hig h 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-trimethy lsilylprop-1-ene with alpha,beta-unsaturated ketones in the presence o f caesium carbonate.