Direct Amidation of Carboxylic Acids Catalyzed by <i>ortho</i>-Iodo Arylboronic Acids: Catalyst Optimization, Scope, and Preliminary Mechanistic Study Supporting a Peculiar Halogen Acceleration Effect
作者:Nicolas Gernigon、Raed M. Al-Zoubi、Dennis G. Hall
DOI:10.1021/jo3013258
日期:2012.10.5
synthetic products motivates the development of catalytic, direct amidation methods employing free carboxylic acids and amines that circumvent the need for stoichiometric activation or coupling reagents. ortho-Iodophenylboronic acid 4a has recently been shown to catalyze direct amidation reactions at room temperature in the presence of 4A molecularsieves as dehydrating agent. Herein, the arene core of ortho-iodoarylboronic
Solid-supported ortho-iodoarylboronic acid catalyst for direct amidation of carboxylic acids
作者:Nicolas Gernigon、Hongchao Zheng、Dennis G. Hall
DOI:10.1016/j.tetlet.2013.06.043
日期:2013.8
Amides are a ubiquitous class of organic compounds endowed with great utility. There is a need for simple and effective catalytic methods for their direct formation from carboxylic acids and amines as a way to avoid the use of coupling reagents. We have designed a recyclable resin-supported derivative of 5-methoxy-2-iodophenylboronic acid as a heterogeneous catalyst active in ambient conditions for promoting direct amidations of aliphatic carboxylic acids and amines. The optimal, practical procedure involves a simple double-filtration to isolate the amide product while separating the catalyst from residual molecular sieves. (C) 2013 Elsevier Ltd. All rights reserved.