Isolation and Characterization of Silyl Enol Ether Intermediates in the Synthesis of 5,6,9,10–Tetrahydro-7,8-benzocyclooctenedione

The 5,6,9,10-tetrahydro-7,8-benzocyclooctenedione 4 has been synthesized through fragmentation of a bicyclo[4.2.0]octane system using an acyloin reaction on the trans-2,3-dicarboethoxy-1,2,3,4-tetrahydronaphthalene 1 in the presence of trimethylchlorosilane (TMCS). The two intermediates of this reaction, bis(trimethylsiloxy) derivatives 2 and 3, have been isolated and characterized.