Heterodienophile Additions to Dienes

摘要: Diels–Alder reactions of heterodienophiles have been known for decades, but only recently has this methodology become widely accepted by the synthetic community. There is enormous diversity in structural types compounds which can act as heterodienophiles, and a wide array heterocyclic adducts be prepared via these [4 + 2] cycloadditions. It seems clear that hetero span range mechanism from concerted to stepwise ionic processes. In many instances, mechanistic information totally lacking. The discussion below therefore classifies rather than class. Only major synthetically useful included. Moreover, significant regio- stereo-chemical features exemplified much possible using reported cases. Other more comprehensive specialized reviews1 should consulted older material obscure