Synthesis Of Chiral Biscarboline N,N'-dioxide Derivatives And Their Application For Asymmetric Catalysis Reaction

Chiral amines are key intermediates for many compounds and have been widely used in medicines,pesticides,foods and other fields.In this study,L-tryptophan was used as a major starting material in synthesis of chiral axial biscarboline N,N'-dioxide catalysts.Ketimines andb-enamine esters were reduced via hydrosilylation to afford the correpsonding chiral amines with high enantioselectivities catalyzed by the chiral biscarboline N,N'-dioxide catalysts.There are three chapters in this thesis.The first chapter involves reviewing the asymmetric reductions catalyzed by chiral N,N'-dioxide compounds,including the asymmetric Sakurai-Hosomi reactions,Michal reactions,epoxy ring-opening reactions,and asymmetric Aldol reactions.In the second chapter,five chiral alcohols were synthesized from L-tryptophan via several steps.They were employed in catalytic enantioselective reductions of ketimines with trichlorosilane for the first time.The experimental results showed that the chiral biscarboline alcohols have moderate enantioselectivities.After oxidation of nitrogen of the biscarbolines,these chiral N-O-containing biscarboline alcohols were applied for asymmetric reduction of 14 different structures of ketimines with trichlorosilane.The reduction of ketimines with the catalyst at -5?was successfully accomplished in 24 h,leading to conversion yields up to 89%~97%and the enantioselectivity up to 99%.In the third chapter,?-enamine esters were used in asymmetric reaction by the chiral N,N'-dioxide with good catalytic enantioselectivities.In the experiments,the catalysts can be catalyzed within 24 hours under conditions at -10?.The yields can be 87%~92%,and the enantioselectivity can be high up to 99%.