Synthesis of bicyclo[2.2.2] System having ?,??or ???-enone with ?-Keto Conjugation and Sterically Hindered Group at the Bridgehead Position

Bicyclo [2.2.2] system having, or -enone with -Keto Conjugation is an important class of compound in terms of synthetic organic chemistry due to their versatile role as building blocks of many natural products and their interesting photochemical behaviors. Herein we have reported the synthesis of such bicyclo compounds having bulky group at the bridgehead position through Diels Alder reaction between 3-trimethylsilioxycyclohexa-1, 3-diene and acetylenic ketones, followed by hydrolysis of the silyloxy adduct. It was observed that unlike previously reported diene, these dienes are highly susceptible towards even trace amount of moisture. Modifying the reaction condition including filtration under argon atmosphere gave the desired Bicyclo [2.2.2] system having sterically hindered group like phenyl and isopropenyl group at the bridgehead position