The Regiocontrollable Enantioselective Synthesis of Chiral Trifluoromethyl-Containing Spiro-Pyrrolidine-Pyrazolone Compounds via Amino-Regulated 1,3-Proton Migration Reaction
as catalyst, the 1,3-dipolar cycloaddition of α,β-unsaturated pyrazolone with diethyl2-((2,2,2-trifluoroethyl)imino) malonate offered adducts in excellent yields, dr, and ee. While the cyclohexanediamine-derived squaramide was employed, the reaction afforded a series of structure isomers through a switched umpolung reaction.
描述了含CF 3的螺-吡咯烷-吡唑啉酮化合物的氨基控制区域发散不对称合成。以生物碱衍生的方酸酰胺为催化剂,α,β-不饱和吡唑啉酮与 2-((2,2,2-三氟乙基)亚氨基)丙二酸二乙酯的 1,3-偶极环加成反应以优异的收率、dr 和 ee 提供加合物。虽然使用了环己二胺衍生的方酸酰胺,但该反应通过转换的 umpolung 反应提供了一系列结构异构体。
Enantioselective Synthesis of Unsymmetrical Diaryl-Substituted Spirocyclohexanonepyrazolones through a Cascade [4+2] Double Michael Addition
作者:Jin-Xin Zhang、Nai-Kai Li、Zhao-Min Liu、Xiao-Fei Huang、Zhi-Cong Geng、Xing-Wang Wang
DOI:10.1002/adsc.201200925
日期:2013.3.11
ortho‐fluorobenzoic acid is an efficient catalyst system for the doubleMichaeladdition of arylidenepyrazolones with α,β‐unsaturated ketones, providing chiral unsymmetrical 6,10‐diaryl‐substituted spiro[cyclohexanone‐pyrazolone] derivatives in high yields (up to 98%) with good diastereoselectivities and excellent enantioselectivities (up to 88:12 dr, 99% ee).
作者:Madavi S. Prasad、Murugesan Sivaprakash、A. Palanichamy
DOI:10.1039/d2ob01085b
日期:——
For the first time, [4 + 2]-annulation of in situ generated trienamine from 2-(E)-benzylidine-3-pyrrolidinyl acraldehyde with pyrazolone olefins has been developed to give hexahydrospiroindole pyrazolones with high chemo- and stereoselectivity.