New synthesis and cyclopropanation of α-phenylselanyl α,β-unsaturated ketones with non-stabilized phosphorus ylides

A general method for the preparation of alpha-phenylselanyl enones is described. Phosphorus ylides react with these alpha-phenylselanyl enones in a 1,4-addition, leading to cyclopropanes and/or dihydrofurans, depending on the substitution pattern. This unusual reactivity is due to the phenylselanyl moiety, hindering the carbonyl of the enone and making it less prone to 1,2-additions or conjugate addition by electronic effects. (C) 2008 Elsevier Ltd. All rights reserved.