Chiral Tetrahydroquinoline And Chiral ?-Trifluorotertiol Catalyzed By Chiral Phosphoric Acids

This thesis mainly focused on the development of new asymmetric reaction catalyzed by chiral phosphoric acids.A series of chiral 2-substituted tetrahydroquinolines and ?-trifluoromethyl tertiary alcohols were constructed in a concise manner.In the first part,an efficient method merging chiral phosphoric acid catalysis with visible-light induction for the highly enantioselective synthesis of tetrahydroquinolines has been developed.This mild process directly transformed 2-aminoenones into 2-substituted tetrahydroquinolines with excellent enantioselectivities through a relay visible-light induced cyclization/chiral phosphoric acid catalyzed transfer hydrogenation reaction.The effects of catalyst,solvent,reductant loading,and reaction concentration were studied,and the optimal reaction conditions(5 W LEDs,2 mol% BINOL-derived chiral phosphoric acid,0.2 M in ethyl acetate,and 3.0 equivalent of Hantzsch ester)were obtained.Under the optimal conditions,a variety of substituted 2-aminoenones were attempted to obtain high yield(up to 98%)and excellent enantioselectivity(up to >99% ee).In the second part,an efficient chiral phosphoric acid-catalyzed asymmetric Friedel–Crafts alkylation of indoles with benzothiazole-bearing trifluoromethyl ketone hydrates as electrophilic reagents has been developed.This mild organocatalytic reaction proceeded well with low catalyst loading to afford a range of enantioenriched ?-trifluoromethyl tertiary alcohols containing both benzothiazole and indole rings with excellent yields and enantioselectivities.In this reaction,the effects of catalyst,solvent,and additive were studied,and the optimal reaction conditions(1 mol% SPIROLderived TRIP,0.1 M in dichloromethane,and 5 ? MS as additive)were obtained.Under the optimal reaction conditions,a variety of substituted were attempted to obtain yielded high yield(up to 99%)and excellent thiophene selectivity(up To >99% ee).The reaction was in the double activation mode and proposed a possible transition state.A gram-level reaction with a very low catalyst loading(0.2 mol%)was performed well with quantitative 93% ee,and optically pure product was easily obtained by a simple recrystallization achieved.