Synthesis of Highly Functionalized Allene-Appended Oxindoles and 2-Oxo-1,2-dihydroindol-3-ylidene-2,5-dihydrofurans via Claisen Rearrangement and Cyclization

Abstract

Synthesis of highly functionalized allene appended oxindole derivatives from vinyl propargyl ether derivatives of Morita-Baylis-Hillman adducts of isatin via Claisen rearrangement has been achieved. Synthetic utility of the allene derivatives obtained has been demonstrated with the synthesis of methyl 2,5-dihydro-5-methyl-2-(1-methyl-2-oxoindolin-3-ylidene)furan-3-carboxylates in a one-pot cyclization reaction under basic conditions. A plausible mechanism of the reaction is presented.