Studying On Asymmetric Nazarov Reaction Of Divinyl Ketones Catalyzed By Chiral–Al(Ⅲ)

Five carbon ring structure is widely existed in many natural products and biological active molecules. As one of the most direct and effective methods for constructing cyclopentenones, Nazarov reaction has received increasing attention from chemical workers, and has been widely used in the synthesis of natural products and biological active molecules, such as(-)-Rocaglamide. Since the first asymmetric catalytic Nazarov reaction was reported, some development in this area has been made. However, due to the nature of the reaction, there are still many deficiencies.In this thesis, we have done in-depth and meticulous work at the utilization of non-ester-activated dienones which show low activity and poor diastereoselectivity in asymmetric Nazarov reactions. We have designed and synthesized a series of chiral Salalen-Al complexes. After screening the catalysts and optimizing reaction conditions such as temperature, reaction time and additive,the optimal reaction conditions was obtained. Under which, the reaction proceed in good yield(up to 78%),high diastereoselectivity(up to 80:20 dr) and good enantioselectivity(up to 84% ee).