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
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 (
Highly Selective Synthesis of β-Amino Carbonyl Compounds over ZSM-5-SO<sub>3</sub>H under Solvent-free Conditions
ZSM-5-$SO_3H$ efficiently catalyzed the one-pot three-component Mannich reaction of aldehydes, anilines, and ketones. $\beta}$-Aminocarbonyl compounds were obtained in reasonable yields and excellent stereoselectivities when the reaction was carried out at room temperature under solvent-free conditions. Simple experimental conditions and product isolation procedure makes this protocol potential for the development of clean and environment-friendly strategy for the synthesis of $\beta}$-amino-ketones. The catalyst was recovered and reused for subsequent runs.
In this article, we present a convenient and green method for synthesis of β-amino carbonyl compounds through ball-milling technique by using aqueous formic acid, which is an inexpensive and highly efficient catalyst. This multi-component reaction was done at room temperature with high anti-selectivity and easy workup. The use of solvent-free ball-milling technique helped to have high yields and more cleanness, besides omitting the need for solvent in this method.
afforded corresponding Mannich adducts. In the case of cyclohexanone, stereoselectivity was changed depending on the nature of the substitution on benzaldehydes, in which, moderate electron-donating and electron-withdrawing groups afforded the anti isomer as major products, but strongly electron-donating substituted benzaldehydes led to syn isomer as the major Mannich adducts. Mannich reaction with cycloheptanone