Six-membered-ring annulation via a conjugate addition/alkylation sequence using functionalized aryllithium reagents and vinyl sulfones

Article abstract of DOI:10.1021/jo00314a026

A new method, which is a one-flask procedure involving addition of substituted aryllithium reagents 6 to vinyl sulfones 8 and 9 followed by spontaneous intramolecular alkylation of the resulting α-lithio sulfones, has been developed for the annulation of tetrahydronaphtalene moieties onto preexisting carbon frameworks.The aryllithium reagents employed in this study are the previously investigated intermediates obtained by the chemoselective lithium-halogen exchange reactions of simple as well as oxygenated o-halo-β-phenethyl halides 5.The annulation products 11 and 12 may be subjected to various further transformations which should makethe overall sequences of considerable utility in the synthesis of steroids and other polycyclic systems.