Enantioselective syntheses of (R)-3-phenyl GABA, (R)-baclofen and 4-arylpyrrolidin-2-ones
摘要:
Enantioselective synthesis of (R)-4-amino-3-phenylbutyric acid and (R)-baclofen has been achieved through a diastereoselective conjugate addition of cyanide to enantiomerically pure 2-(2-arylethenyl)oxazolines, followed by chemoselective reduction into cyclic amidines. Copyright (C) 1996 Elsevier Science Ltd
A series of novel l-proline derived tertiary amine bifunctional organocatalysts 9 are reported, which were applied to the asymmetric Michaeladdition of dithiomalonates 2 to trans-β-nitroolefins 1. The reaction proceeded in high yields (up to 99%) with high enantioselectivities (up to 97% ee). The synthetic utility of this methodology was demonstrated in the short synthesis of (R)-phenibut in high
A series of chiral polysulfonate cyclohexyldiamine-Ni(II) catalysts were prepared via sulfur (VI) fluoride exchange click-reactions. The catalysts exhibited good catalytic activity and enantioselectivity in the Michaeladdition of malonates to nitroalkenes. The excellent recyclability of the catalysts was demonstrated via the reuse of the privileged catalyst 7a for ten times. The results provide a
作者:A. N. Reznikov、V. A. Ostrovskii、Yu. N. Klimochkin
DOI:10.1134/s1070428018110155
日期:2018.11
Nonracemic 3-substituted 4-(1H-tetrazol-1-yl)butanoic acids, analogs of the neurotropic drugs phenibut, tolibut, and baclofen, were synthesized by a three-component reaction of the R-isomers of the corresponding amino acids, triethyl orthoformate, and sodium azide. The key stage of the synthesis is the asymmetric addition of diethyl malonate to nitroalkenes, catalyzed by a Ni(II) complex of (S,S)-N
Highly Enantioselective Michael Addition of Nitroalkanes to Enones and Its Application in Syntheses of (R)-Baclofen and (R)-Phenibut
作者:Feng Sha、Xin-Yan Wu、Xing-Tao Guo、Jie Shen
DOI:10.1055/s-0034-1380203
日期:——
enantioselectivities. A highly enantioselective Michael addition of nitroalkanes to α,β-unsaturated ketones was developed. In the presence of a chiral primary amine–thiourea catalyst based on dehydroabietic amine, γ-nitro ketones were obtained with excellent enantioselectivities (up to 99% ee) and in up to 96% yield. This protocol was successfully applied in asymmetric syntheses of (R)-baclofen and (R)-phenibut
Enantioselective organocatalytic Michael reactions using chiral (<i>R</i>,<i>R</i>)-1,2-diphenylethylenediamine-derived thioureas
作者:Jae Ho Shim、Min Ji Lee、Min Ho Lee、Byeong-Seon Kim、Deok-Chan Ha
DOI:10.1039/d0ra03550e
日期:——
Although the Michael addition is a very well-known and widely applied reaction, cost-effective, metal-free, and readily prepared organic catalysts remain rare. A chiral, bifunctional, (R,R)-1,2-diphenylethylenediamine-derived thiourea organic catalyst was developed and applied to asymmetric Michael additions of nitroalkenes under neutral conditions. Generally, fluorine-substituted thiourea catalysts
尽管迈克尔加成反应是一种众所周知且应用广泛的反应,但具有成本效益、不含金属且易于制备的有机催化剂仍然很少见。开发了一种手性、双功能、( R , R )-1,2-二苯基乙二胺衍生的硫脲有机催化剂,并将其应用于中性条件下硝基烯烃的不对称迈克尔加成。通常,氟取代的硫脲催化剂在中性条件下表现出高化学产率和对映选择性。温和的反应对许多官能团具有耐受性,并提供了良好的产率,以及迈克尔加合物的高非对映和对映选择性。通过合成生物活性化合物 ( R )-Phenibut 证明了转化的效用。