Stille/Diels-Alder reaction sequences:: Diversity-oriented access to novel steroids

An efficient, diversity-oriented approach to novel steroid analogues possessing a C-5 beta configuration begins with the Stille cross-coupling of enantiomerically pure cycloalkenylstannane trans-2 and enol triflate 3. The resulting diene trans-4 engages in Diels-Alder cycloaddition reactions with a range of dienophiles to give, after removal of protecting groups, biologically interesting 6,7-disubstituted steroid analogues.