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
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.