Synthesis of benzo[g]isochromenes through Photo-Dehydro-Diels-Alder reaction

Abstract

The Photo-Dehydro-Diels-Alder (PDDA) reaction is shown to be a versatile method for the preparation of highly functionalized naphthalenes. Thus, ketones 1 could be cyclized to the 1H-benzo[g]isochromen-4-(3H)-ones 11 and 12, mostly in good yields. The influence of various substituents on the regioselectivity of the reaction was investigated, and the mechanism is discussed based on theoretical calculations. © 2006 Verlag Helvetica Chimica Acta AG.