VERSATILE SYNTHESIS OF BICYCLO[4.3.0]NONENES AND BICYCLO[4.4.0]DECENES BY A DOMINO HECK-DIELS-ALDER REACTION

摘要

Various 2-bromo-1,6- and 2-bromo-1,7-dienes were cyclized under palladium catalysis producing vicinal exodimethylenecycloalkanes which reacted with dienophiles (either present during the cyclization or added afterwards in a one-pot process) to give bicyclo[4.3.0]nonene and bicyclo[4.4.0]decene derivatives in good to excellent yields. Among the examples reported are the first cases of intramolecular Heck reactions with a (bromomethylene)cyclopropane starter or/and a methylenecyclopropane terminator which occur without ring opening of the cyclopropyl group. Copyright (C) 1996 Elsevier Science Ltd [References: 65]