A binary acid system has been developed that features an air‐stable organometallic precursor, titanocene dichloride, and simple organic cooperativeBrønstedacids, which allowed for mild and highly efficient Mannich reactions of both aryl and alkyl ketones with excellent yields and satisfactory diastereoselectivity. Mechanistic studies, including 1H NMR titration, X‐ray structure analyses as well as
已经开发了一种二元酸体系,其特征是具有空气稳定性的有机金属前体,二茂钛二氯化物和简单的有机协作布朗斯台德酸,可实现芳基和烷基酮的温和高效的曼尼希反应,并具有优异的收率和令人满意的非对映选择性。机理研究,包括1 H NMR滴定,X射线结构分析以及催化活性物质的分离,阐明了这种新的二元酸体系的巨大协同作用。
The Scope of the Direct Proline-Catalyzed Asymmetric Addition of Ketones to Imines
作者:Wolfgang Notz、Shin-ichi Watanabe、Naidu S. Chowdari、Guofu Zhong、Juan M. Betancort、Fujie Tanaka、Carlos F. Barbas
DOI:10.1002/adsc.200404114
日期:2004.8
A full account of catalytic direct asymmetric Mannich-type reactions is presented describing the scope of amino acid-catalyzed additions of unmodified ketones to a large variety of imines. These reactions are performed under very mild, operationally simple, and environmentally friendly and benign conditions employing a one-pot, three-component protocol as well as preformed imines. Typically, products
One-pot three-component Mannich-type reaction catalyzed by trifluoromethanesulfonic acid in water
作者:Gang Li、Hankui Wu、Zhiyong Wang、Xianli Wang
DOI:10.1134/s0023158411010113
日期:2011.2
One-pot three-componentMannich-typereaction of ketones, aldehydes and amines was efficiently catalyzed by liquid trifluoromethanesulfonic acid in water at ambient temperature. The high yield of corresponding β-amino ketones compounds were achieved. The proposed method is mild, green, simple and efficient.
The remarkable activation effect of alcohol solvent on kinetically inert titanocene dichloride was found to promote rapid three-component Mannichreactions. NMR and ESI-MS analyses as well as a control experiment of catalytic active species elucidated that the coordination of MeOH to the titanocene moiety unleashed the Lewis acid [Cp2Ti(OMe)2] and Brønsted acid HCl, which led to the enhanced catalytic