Discovery Of New C-H Oxidative Transformations Via Self-hydride Transferring Strategy

Our research group has been devoted to exploring new reactions via the self-hydride transferring strategy.In this thesis,we discovered a Ru-catalyzed 1,3-oxazinanes rearrangement reaction and its application in the synthesis of 1,3-aminoalcohols.Based on this work,a direct Julia-olefination of alcohol through a self-hydrogen transferring process has been developed.(1)A highly efficient ruthenium-catalyzed stereospecific N-demethylative rearrangement of isoxazolidines to synthetically useful N-H-1,3-oxazinanes via hydrogen transfer has been developed.We furhter developed a one-pot version for the synthesis of 1,3-oxazinidine directly and selectively with N-Me nitrones and alkenes.A wide range of nitrones and olefins with either aliphatic or aromatic substituents could be transformed.(2)Above method has been used to synthsize cis-1,3-aminoalcohols.1,3-Oxazinanes are useful building blocks,which can be further converted to N-H-1,3-aminoalcohols by hydrolysis or N-Me cis-1,3-amino alcohol by reduction in one step.This new method was used in a three-step gram-scale total synthesis of ceramide inhibitor HPA-12 in overall 24%yield.(3)In furhter study,a direct Julia-olefination of alcohols has been desicovered via the self-hydride tranferring strategy.No extra reductants are needed for this reaction since alcohols work as double sources of aldehydes and the hydride.Generally high yields were given for both terminal and highly(E)-selective internal olefins.