The Siudy Of Enantioselective Brominination/Semipinacol Rearrangement Reaction And Prins-Pinacol Rearrangement Reaction

Quaternary carbon exists widely in active natural products and drug molecules. However, the construction of quaternary carbon has always been a challenge in chemistry, especially all-carbon quaternary carbon. Semipinacol rearrangment reaction is an effective method for the construction of quaternary carbon. Our research group has always been working on semipinacol rearrangement reaction. In this thesis, we constructed multi-functional all-carbon quaternary carbon in the methods of bromination/Semipinacol rearrangement and Prins-Pinacol rearrangement.Part I:The study of enantioselective bromination/Semipinacol rearrangement reaction. As early as2003, our research group had reported bromination/Semipinacol rearrangement reaction. Then Lycoramine was synthesized using this method as a key reaction. But the enantioselective bromination/Semipinacol rearrangement of simple allyl alcohol has not been reported before our research. We developed an efficient and highly enantioselective bromination/Semipinacol rearrangement reaction of simple allyl alcohol with5mol%(DHQD)2PYDZ as catalyst and NBS as bromine source, in which a β-bromoketone containing chiral all carbon quaternary stereogenic center was reported for the first time.Part II:The study of Prins-Pinacol rearrangement reaction. Prins-Pinacol rearrangement reaction has been widely used in the synthesis of natural products, but the catalytic asymmetric reaction has not been reported. In this thesis, we use chiral protonic acid and Lewis acid as catalyst to catalyze this reaction. Although the result is not so good, it laid a foundation for later study.