Asymmetric Reactions Catalyzed By Chiral Tertiary Amine

Based on the diverse activation modes of chiral tertiary amines, this dissertation focused on the development of asymmetric reactions catalyzed by chiral tertiary amines, and a series of important chiral functional molecules were efficiently constructed.Four parts are included in this dissertation:Part Ⅰ:A SN2’/SN2’cascade reaction employing diazo esters as nucleophiles and Morita-Baylis-Hillman (MBH) carbonates as electrophiles in the catalytic asymmetric synthesis strategy for the construction of enantiomerically enriched α-allylic diazo esters based on chiral tertiary amine catalysis has been developed. The development of this process partially build upon our discovery of2,2,2-trifluoroethyl diazoacetate (TFEDA) as a superior nucleophilic reagent. The utility of the products was demonstrated by rapid synthesis of a number of optically pure N-heterocycles.Part Ⅱ:Based on the work of Part Ⅰ, a convenient and efficient synthetic strategy to afford highly functionalized pyridazines has been developed resulting from the reduction of above α-allylic diazo esters. This tertiary amine mediated two-steps one-pot reaction between readily available MBH carbonates and diazo compounds could be achieved rapidly without any harsh reaction conditions.Part Ⅲ:As part of an ongoing project on the activation of diazo compounds without metal catalyst, a novel halogenation/semipinacol rearrangement of diazo compounds catalyzed by tertiary amines has been realized. This reaction is valuable and versatile since the introduction of halo-quaternary carbon into the ketone compounds could be completed effectively under mild conditions. To further realize the reaction enantioselectivity, we examined a number of chiral tertiary amines and varied reaction parameters, which led to the moderate enantioselectivity of the products.Part Ⅳ:Due to the noncovalent character of the substrate (activated O-H/N-H)-chiral tertiary amine catalyst interaction, a new oxa/aza-Michael-Michael cascade strategy between (E)-2-(2-nitrovinyl)phenol/aniline derivatives and methyleneindolinones for the construction of enantiomerically enriched rigid spiroarchitectures fused oxindole with chroman/tetrahydroquinoline has been developed. The analogous skeletons are frequently encountered in biologically active natural products and pharmaceuticals. Moreover, we believe that the chiral tertiary amine catalytic cascade strategy demonstrated here may be utilized in other asymmetric reactions to efficiently produce chiral materials, particularly the optically active chroman/tetrahydroquinoline derivatives.