摘要:
Palladium-catalyzed cross-coupling of alkenylzine reagents, bearing the C,D-ring/side chain portion, and (Z)-1-iodo-1,3-bis-exocyclic dienes (as A-ring precursors), provides a mild, convergent entry to the vitamin D skeleton, that is suitable for the synthesis of thermally labile derivatives such as those bearing substituents on the triene system.