ELECTRON-DEFICIENT DIENES .1. NORMAL AND INVERSE ELECTRON DEMAND DIELS-ALDER REACTIONS OF THE SAME CARBON SKELETON

The synthesis of compound 11, which features a diene moiety bearing el ectron withdrawing groups at the 1 and 3 positions, and its completely regioselective inverse electron demand Diels-Alder reactions with 1,1 -diethoxyethylene, ethyl vinyl ether and styrene are described. Endo a ddition is preferred. The direct synthetic precursor of 11, in which o ne of the electron withdrawing groups (a ketone) is protected, partici pates in normal electron demand Diels-Alder reactions with 1,4-naphtho quinone and N-phenylmaleimide, but is unreactive towards 1,1-diethoxye thylene. Copyright (C) 1996 Elsevier Science Ltd