1,2-Bis(trimethylsiloxy)cyclobutene has been used in the synthesis of:functionalized decalins, required for the total synthesis of various sesquiterpenes and diterpenesangularly substituted bicyclo[4.3.0]nona-2,5-diones and bicyclo-[4.4.0]deca-2,5-diones3-methoxyestra-1,3,5,8,14-pentaen-17-one