A novel Mgl2 mediated unusual dimerization-spirocyclopropanation of bromo isomerised Morita-Baylis-Hillman adduct of isatin: a facile synthesis of 3-spirocyclopropane-2-oxindole derivatives

A novel magnesium iodide mediated unusual dimerization-spirocyclopropanation of bromo isomerised Morita-Baylis-Hillman adducts of isatin afforded highly functionalized 3-spirocyclopropane-2-oxindole derivatives as regioisomers in good combined yield. It has been observed that the regioselectivity is dependent on the nature of electron withdrawing group at the activated position. A plausible mechanism involving organomagnesium reagent has been proposed. (C) 2011 Elsevier Ltd. All rights reserved.