A water-soluble Brønstedacid, 5-sulfosalicylic acid, efficiently catalyzed the direct three-component Mannich reactions of cyclohexanone and 3-pentanone in pure water. 21 Examples of Mannich reactions were presented, which afforded the corresponding β-amino ketones with up to 97% yield and decent diastereoselectivities. The acid catalyst can be recycled as an aqueous solution for at least six times
obtained in high yields, with excellent diastereoselectivity, and short reaction time in the presence of a catalytic system comprising nano-Mn(HSO4)2 and a surfactant, for example sodium dodecyl sulfate. Use of mild, environmentally benign reaction conditions, low loading, and ready accessibility are the main features of this new catalyst. Graphical Abstract
Synthesis and structure of the bimetallic organoantimony catalyst and its application in diastereoselective direct Mannich reaction as facile separation catalytic system
A bimetallic organoantimony catalyst with four Lewis/Brønsted acidic/basic sites assembled orderly was successfully synthesized and showed high catalytic efficiency. It has been applied in diastereoselective direct Mannich reaction by adding 0.1 mol% catalyst. This reaction presented unexpected facile separation ability from homogenous solution to heterogeneous solution.
Abstract Tunable organometallic Lewisacidcatalysts were developed by combining salicylic acid (H2-Sal) with benzoic acid (H-Ben), 4-fluorobenzoic acid (H-BenF) and 3-thiophenic acid (H-Th), as coligands for mixed bis-carboxylate titanocene complexes. Three air-stable complexes [Cp2Ti(η1-HSal)(η1-Ben)] (1), [Cp2Ti(η1-HSal)(η1-BenF)] (2) and [Cp2Ti[η1-HSal][(η1-Th)] (3) were prepared in high yields
摘要 以水杨酸 (H2-Sal) 与苯甲酸 (H-Ben)、4-氟苯甲酸 (H-BenF) 和 3-噻吩酸 (H-Th) 作为混合配体,开发了可调有机金属路易斯酸催化剂。双羧酸二茂钛络合物。三种空气稳定配合物 [Cp2Ti(η1-HSal)(η1-Ben)] (1), [Cp2Ti(η1-HSal)(η1-BenF)] (2) 和 [Cp2Ti[η1-HSal][(η1- Th)] (3) 通过水杨酸二茂钛螯合物与羧酸盐配体的反应以高产率制备。通过物理化学和光谱方法充分表征了混合的双羧酸二茂钛配合物。单晶 X 射线衍射研究揭示了 Ti-O(H-Sal) 键距分别为 1.972(3)、1.9245(18) 和 1.912(5) Å,而键距涉及1、2 和 3 的配体为 1.908(3) Å (Ti-OBen)、1.9296(19) Å (Ti-OBenF) 和 1。分别为 945(5) Å (
Stereoselective synthesis of β-amino ketones via direct Mannich-type reaction catalyzed with silica sulfuric acid
作者:Hui Wu、Yang Shen、Li-yan Fan、Yu Wan、Pu Zhang、Cai-fa Chen、Wen-xiang Wang
DOI:10.1016/j.tet.2007.01.015
日期:2007.3
At room temperature, the direct Mannich-type reaction of a variety of in situ generated aldimines using aldehydes and anilines with ketones in a three-component reaction was efficiently catalyzed by silica sulfuricacid (SSA) in EtOH. This rapid reaction afforded the corresponding β-amino ketones in good yields with excellent stereoselectivities and catalyst was recyclable.