有機非鏡像催化[3+2]環化加成反應製備2,3,4,5-四取代吡咯啶衍生物

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2020

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早期合成吡咯啶,反應的條件嚴苛;合成多取代吡咯啶(pyrrolidine)及其衍生物,在製藥界是重要一環1, 2, 3。本研究藉由溫和的條件,在常溫下於1,4-二氮雜二環[2.2.2]辛烷鹼(1,4-diazabicyclo[2.2.2]octane)(5 mol%)的催化反應,以乙腈(acetonitrile)為反應溶劑,利用(E)-二乙基-2-((2-羥基芐基)氨基)丙二酸酯(E)-diethyl-2-((2-hydroxybenzylidene)amino)malonate)4, 5作為親核基,同時利用具有拉電子基的(E)-2-苯磺醯基-5-苯基戊烷-2,4-乙腈((E)-2-benzenesulfonyl-5-penta-2,4-dienenitrile)6作為親電子基,進行1,6-加成反應(1,6-addition reaction) 7及[3+2]環化加成反應([3+2]cyclization addition reaction),成功地合成多取代的吡咯啶化合物8, 9。反應受到官能基推拉電子之立體效應影響,使得產率略有不同,其產率都有不錯的表現(47-93%)。
In the early synthesis of pyrrolidine, the reaction conditions were quite severe. However, in the pharmaceutical industry, the synthesis of such natural products is an important part. The conventional synthesis of substituted pyrrolidine requires multiple steps under harsh reaction conditions. In this study, we will present under mild conditions, at room temperature in the catalytic reaction of 1,4-diazabicyclo [2.2.2] octane (5 mol%), and with acetonitrile as the reaction solvent, using (E)-diethyl-2-(( 2-hydroxybenzylidene) amino) malonate as a nucleophilic group, while using (E)-2-benzenesulfonyl-5-penta-2,4-dienenitrile with an electron-withdrawing group and various functional groups as an electrophilic group starting material 1,6-addition reaction and [3 + 2]cyclization addition reaction, could successfully synthesize multi-substituted pyrrolidine compounds. The reaction is affected by the stereo effect of the push-pull electrons of the functional group, which makes the yield slightly different, and the yield has a good performance(47-93%). The chemical structures of the substituted pyrrolidine was determined by 1H NMR, 13C NMR, IR, HRMS, and the relative stereochemistry of some products were assigned by single crystal x-ray analysis.

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高度非立體選性, 無金屬合成, 多取代的吡咯啶, 1, 6 加成反應, Highly Diastereoselective, Metal-free synthesis, polysubstituted pyrrolidine, 1,6-addition reaction

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