Traceless Solid-Phase Synthesis of Cyclopenta[c]quinolines and Cyclopenta[c]chromenes via Hetero [6+3] Cycloadditions of Fulvene. A Facile Approach to the 11-Heterosteroids Framework

The hetero [6+3] cycloaddition of fulvenes to benzoquinones and iodoanilines provides an efficient route to the synthesis of cyclopenta[c]-4H-chromen-8-ol, benzo[d]cyclopenta[e]-3H-3-azin-8-ol and other 11hetero steroids. The structure of the cyclopenta[c]chromene skeleton was confirmed by the X-ray structure analysis of the p-bromobenzoate of 39. A small library consisting of 110 examples was prepared by reacting benzoquinones or iodoanilines with resin 17.