Chiral Ammonium Betaines: A Bifunctional Organic Base Catalyst for Asymmetric Mannich-Type Reaction of α-Nitrocarboxylates
作者:Daisuke Uraguchi、Kyohei Koshimoto、Takashi Ooi
DOI:10.1021/ja8041004
日期:2008.8.1
A chiralammoniumbetaine, an intramolecular ion-pairing quaternary ammonium aryloxide 3, has been designed and its vast potential as an enantioselective organic base catalyst has been successfully demonstrated in the highly enantioselective direct Mannich-type reaction of alpha-substituted alpha-nitrocarboxylates 2 with various N-Boc imines 1. The present study provides a conceptually new approach
A chiral molecular recognition approach to the formation of optically active quaternary centres in aza-Henry reactions
作者:Kristian Rahbek Knudsen、Karl Anker Jørgensen
DOI:10.1039/b500618j
日期:——
An approach to asymmetric catalysis based on chiral molecularrecognition by the combination of chiral Lewis acids and chiral organocatalysis for the formation of optically active quarternary centers in the aza-Henry reaction is presented; this procedure leads to products with up to 98% ee and a diastereomeric ratio of 14 : 1 in excellent yields with catalyst loadings of 5 mol%.
A Bench-Stable Homodinuclear Ni<sub>2</sub>−Schiff Base Complex for Catalytic Asymmetric Synthesis of α-Tetrasubstituted <i>anti</i>-α,β-Diamino Acid Surrogates
Catalyticasymmetric direct Mannich-type reactions of α-substituted nitroacetates using a new bench-stable homodinuclear Ni2−Schiff base 1b complex are described. The Ni2−1b complex gave Mannich products, precursors for anti-α,β-diamino acids with an α-tetrasubstituted carbon stereocenter, in >99−91% ee. The Ni2−1b complex was also applicable to direct Mannich-type reactions of malonates and β-keto
Organocatalytic conjugate addition of α-nitroacetates to β,γ-unsaturated α-keto esters and subsequent decarboxylation: synthesis of optically active δ-nitro-α-keto esters
作者:Rui-jiong Lu、Wen-tao Wei、Jin-jia Wang、Shao-zhen Nie、Xue-jing Zhang、Ming Yan
DOI:10.1016/j.tet.2012.09.014
日期:2012.11
Organocatalytic asymmetric conjugate addition of tert-butyl nitroacetates to β,γ-unsaturated α-keto esters has been developed. The subsequent in situ hydrolysis–decarboxylation of the adducts provided 5-nitro-2-oxopentanoates. A pyrrolidine-based thiourea-tertiary amine was identified as the best catalyst. A number of γ-aryl, γ-alkyl, and γ-heteroaryl β,γ-unsaturated α-keto esters and α-substituted
OPTICALLY ACTIVE DINICKEL COMPLEX AND METHOD FOR PRODUCING OPTICALLY ACTIVE AMINE USING THE OPTICALLY ACTIVE DINICKEL COMPLEX AS CATALYST
申请人:Shibasaki Masakatsu
公开号:US20100298559A1
公开(公告)日:2010-11-25
There is provided a novel optically active dinickel complex and/or a production method of an optically active amine by an asymmetric Mannich reaction using the dinickel complex as a catalyst. An optically active dinickel complex of Formula (I) or Formula (I′):
[where R
0
, R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, and R
7
are each independently a hydrogen atom, a halogen atom, a C
1-10
alkyl group or a C
1-10
alkoxy group, etc., R
2
and R
3
together form, together with a benzene ring bonded to them, a naphthalene ring, etc. A novel production method of an optically active amine by an asymmetric Mannich reaction using the dinickel complex as a catalyst.