Palladium catalyzed alkylative cyclization useful in synthesis of vitamin d and analogues

摘要: An alkylative cycloaddition method is provided that particularly useful for the synthesis of many Vitamin D analogues with differing side chains. Thus, a preferred having chain R1 where substantially geometrically pure first precursor structure (I), and second are provided, being 1,7 enyne. These precursors reacted in presence palladium catalyst to form compounds (II), R2 hydrogen, hydroxyl, lower alkoxy, fluorine, or protecting group, R3 group.