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
Direct Catalytic Asymmetric Synthesis of <i>anti</i>-1,2-Amino Alcohols and <i>syn</i>-1,2-Diols through Organocatalytic <i>anti</i>-Mannich and <i>syn</i>-Aldol Reactions
作者:S. S. V. Ramasastry、Haile Zhang、Fujie Tanaka、Carlos F. Barbas
DOI:10.1021/ja0677012
日期:2007.1.1
anti-1,2-amino alcohols and syn-1,2-diols through direct asymmetric Mannich, Mannich-type, and aldol reactions involving unmodified α-hydroxyketones in reactions catalyzed by primary amine-containing amino acids. These reactions exploit (Z)-enamines of α-hydroxyketones in their bond-forming transition states. This study compliments and extends our bioorganic approach to asymmetricsynthesis in these two
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
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.
A novel design of roof-shaped anthracene-fused chiral prolines as organocatalysts for asymmetric Mannich reactions
A new class of artificial anthracene-fused chiral proline catalysts has been synthesized from the Diels-Alder adduct of anthracene and maleic anhydride via lithiation/carboxylation of 6 as a key step. Chiral resolution of racemic amino acids was carried out through the formation of diastereomeric esters with (-)-menthol. The absolute configuration of the chiral amino acid was determined by X-ray crystallographic analysis. The utility of the catalyst was confirmed by effecting asymmetric three-component Mannich reactions between aldehyde, ketone, and amine (yield up to 76%, ee up to 90%). (c) 2006 Elsevier Ltd. All rights reserved.