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.
Simple and inexpensive threonine-based organocatalysts for the highly diastereo- and enantioselective direct large-scale syn-aldol and anti-Mannich reactions of α-hydroxyacetone
作者:Chuanlong Wu、Xiangkai Fu、Shi Li
DOI:10.1016/j.tetasy.2011.06.022
日期:2011.5
Simple and inexpensive threonine-based organocatalysts that promote syn-aldol reactions and three-component asymmetric anti-Mannich reactions of alpha-hydroxyacetone achieving a respectable level of enantioselectivities are reported. The syn-aldol products could be obtained with up to a 99:1 syn/anti ratio and > 99% ee while the anti-Mannich products could be obtained with up to a 96:4 anti/syn ratio and > 99% ee. Catalyst 1c can be used efficiently on a large-scale with the enantioselectivities of the syn-aldol and anti-Mannich reactions being maintained at the same level, which offers a great possibility for application in industry. (C) 2011 Elsevier Ltd. All rights reserved.
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