Isosteviol-amino Acid Conjugates as Highly Efficient Organocatalysts for the Asymmetric One-pot Three-component Mannich Reactions
作者:Yajie An、Qian Qin、Chuanchuan Wang、Jingchao Tao
DOI:10.1002/cjoc.201180272
日期:2011.7
Isosteviol‐amino acid conjugates were synthesized and used as chiral catalysts for the asymmetric three‐component Mannichreaction with hydroxyacetone as donor molecule. Good yields (up to 98%) and excellent stereoselectivities (up to 97:3 dr and 99% ee) were achieved in a short reaction time. In addition, syn‐ or anti‐configurations of α‐hydroxy‐β‐amino carbonyl compounds were obtained as main products
Threonine-surfactant organocatalysts for the highly diastereo- and enantioselective direct anti-Mannich reactions of hydroxyacetone
作者:Chuanlong Wu、Xiangkai Fu、Xuebing Ma、Shi Li、Chao Li
DOI:10.1016/j.tetlet.2010.08.085
日期:2010.11
by the reaction of threonine with acyl chlorides at room temperature in trifluoroacetic acid on a large-scale without protecting groups involved or chromatographic techniques, and those threonine-surfactant organocatalysts mediated the direct asymmetric anti-Mannich reactions of hydroxyacetone and anilines with aldehydes to synthesize anti-1,2-amino alcohols in good yields (75–93%) and highly enantioselectivities
作者:Jacek Chrzanowski、Michał Rachwalski、Adam M. Pieczonka、Stanisław Leśniak、Józef Drabowicz、Piotr Kiełbasiński
DOI:10.1016/j.tet.2015.05.103
日期:2016.5
New polydentate chiral ligands, containing the hydroxyl group, stereogenic sulfinyl group and enantiomeric prolinol moieties were synthesized and proved very efficient catalysts in the asymmetric diethylzinc addition to benzaldehyde, the asymmetric aldol condensation and the asymmetric Mannich reaction. Replacement of the central hydroxyl group with the second prolinol moiety of the same absolute configuration gave new ligands in which the sulfinyl group was not a stereogenic centre anymore, but which proved almost equally efficient as catalysts for the reactions investigated. The absolute configuration of the proline moiety exerted a decisive impact on the stereochemical outcome of these reactions, deciding about the absolute configuration of the products formed. (C) 2015 Elsevier Ltd. All rights reserved.
Continuous Flow Enantioselective Three-Component <i>anti</i>-Mannich Reactions Catalyzed by a Polymer-Supported Threonine Derivative
作者:Carles Ayats、Andrea H. Henseler、Estefanía Dibello、Miquel A. Pericàs
DOI:10.1021/cs5006037
日期:2014.9.5
A series of primary amino acid-derived polystyrene-supported organocatalysts was tested in antiselective Mannidi reactions. The polystyrene-immobilized threonine derivative showed the best performance in threecomponent (hydroxyacetone, anilines, and aldehydes) Mannich reactions to provide anti-beta-amino-alpha-hydroxycarbonyl compounds (11 examples; up to 95% ee), and its use could be extended to dihydroxyacetone and protected hydroxyace-tones (7 examples; up to 90% ee). The high activity depicted by the catalyst has allowed its implementation in continuous flow. Under this operation mode, the supported threonine catalyst produces anti-Mannich adducts with generally higher diastereo- and enantioselectivity than in batch. A family of five different enantioenriched anti-Mannich adducts has been sequentially prepared in flow by passing different combinations of anilines and aromatic aldehydes over the same sample of catalyst. This confirms the suitability of this methodology for the rapid access to small libraries of enantioenriched compounds.
Enantioselective Organocatalytic Mannich Reactions with Autocatalysts and Their Mimics
作者:Xinbo Wang、Yongbo Zhang、Haibo Tan、Yanchao Wang、Peng Han、David Zhigang Wang
DOI:10.1021/jo902500b
日期:2010.4.2
The Mannich reactions previously extensively investigated with organocatalysis of L-proline and other related small molecules were reinvestigated with detailed stercochemical analysis of their autocatalysis pathways, through employment of both the products themselves and their close structural mimics as the catalysts. These organo-autocatalytic processes function as meaningful molecular models toward understanding the origin and maintenance of homochirality under biologically relevant conditions.