Synthetic Studies Toward Cembranoid Diterpene Pavidolide B

Chapter 1 is mainly about the classification of polycyclic furanobutenolidederived cembranoids and norcembranoids.The synthetic progress of some natural products in this family was also summarized.In Chapter 2,the nickel-catalyzed tandem cyclization system developed by our research group was used to construct three chiral centers including one quaternary carbon in one step.At the same time,the synthesis of central five-membered ring and tetrahydrofuran ring had also been completed,which accumulated experience for the subsequent synthesis.5-methoxy(benzyloxy)-substituted cyclization products were synthesized by optimizing the reaction conditions.Dearomatization was also achieved by the oxidation of 5-benzyloxy-substituted product.In Chapter 3,6-methoxy(benzyloxy)-substituted cyclization products were synthesized by screening the most suitable experimental conditions.The corresponding dearomatization reaction was achieved as well.In Chapter 4,by optimizing the experimental conditions of Ni-catalyzed tandem cyclization,a preparation of the cyclization product in gram scale was realized.In addition,the carbon skeleton and all the chiral centers of(–)-Pavidolide B was successfully constructed by the dearomatization and subsequent elaborations,therefore laying the foundation for total synthesis of this molecule.