Studies On Enantioselective Acylation Of Diols

Optically pure diols have.attracted wide attention of chemists as an important class of synthetic building blocks.Currently,there are two main directions in this field:one is the selective protection of chiral substrates especially carbohydrates,the other one is the asymmetric synthesis of chiral diols.In this thesis,we first systematically presented the progress of selective protection of chiral diols in the presence of chiral catalysts,Then we described processes of constructing chiral diol backbones by acylative desymmetrization and acylative kinetic resolution strategies.Based on previous work of other chemists,we developed new strategies and designed new catalysts to address the unresolved problems in this area.The full text Includes following three parts:Chapter 2:Parallel kinetic resolution of unsymmetrical 1,3-diolsWe disclosed parallel kinetic resolution of unsymmetrical terminal 1,3-diols and syn-1,3-diols through oxidative ring opening of benzylidene using dimethyldioxirane in combination with chiral phosphoric acid,which afforded a series of ester products bearing primary or secondary hydroxy group with high yields and excellent enantioselectivities.Meanwhile,this catalytic method could be applied to the selective protection of chiral substrates controlled by catalyst.Chapter 3:Organotin catalyzed enantioselective acylative desymmetrization m eso-1,3-diolWe described a new chiral organotin catalyst based on binaphthyl skeleton and applied it to the enantioselective desymmetrization of meso-1,3-diols employing the"ring closure-ring opening" strategy,which is the first time of highly enantioselective desymmetrization of acyclic alkyl substituted meso-1,3-diols.The application of the catalyst has been further demonstrated through enantioselective kinetic resolution of tran-1,3-diols.Chapter 4:Organotin catalyzed acylative Kinetic resolution of vicinal amino alcohol catalyzedTo further demonstrate the utility of organotin catalysis,a variety of non-natural vicinal amino alcohols were kinetically resolved through acylation of alcohol catalyzed by novel organotin developed by our group under mild reaction conditions.Products and recovered starting materials were obtained in high enantioselectivities.