Study On Synthesis Of Monofluoro-substituted Pyrazole And Asymmetric Mannich Reaction

In this dissertation, we conducted “one pot” tandem transition metalRh2(OAc)4-catalyzed C-H insertion and electrophilic fluorination reaction to provide4-fluoro-pyrazole derivatives; Bifunctional aminophosphine catalyst was used inasymmetric Mannich reaction of malonate derivatives with N-Boc protected imine,and the corresponding products of optically active-aminoesters could be obtained inboth high yields and enantioselectivities. The main contents were as follows:Part1A series of4-fluoro-pyrazole derivatives were synthesized in moderate to goodyields via a “one-pot” tandem procedure involving a Rh2(OAc)4-catalyzed C-Hinsertion and an electrophilic fluorination with N-fluorobenzenesulfonimide (NFSI).The structures of these compounds were confirmed by IR,1H NMR,13C NMR,19FNMR, MS and HRMS as well. Besides, preliminary studies were also done to explorethe possibility of achieving enantiocontrol in this protocol, and a modest ee wasobtained.Part2Dual-reagent organocatalysis with an N-Acyl aminophosphine and methylacrylate: application to the asymmetric Mannich reaction of N-Boc protected imineswith2-fluoro-malonates was achieved. Under this catalytic system, we could obtainthe products in good yields and high enantiomeric excess value. Besides, the possiblemechanism was assumed on the basis of31P NMR,19F NMR.