A new and high yielding synthesis of unstable pyrroles via a modified Clauson-Kaas reaction
作者:Brendon S. Gourlay、Peter P. Molesworth、John H. Ryan、Jason A. Smith
DOI:10.1016/j.tetlet.2005.11.104
日期:2006.1
An investigation of the reaction requirements to effect the Clauson-Kaas pyrrole synthesis led to the formulation of a new procedure that avoids the contact of pyrroles to heat or strongly acidic conditions that cause decomposition of the desired products. The procedure involves mild hydrolysis of 2,5-dimethoxytetrahydrofuran in water to the activated species 2,5-dihydroxytetrahydrofuran that reacts
对影响克劳森-卡斯(Clauston-Kaas)吡咯合成的反应要求的研究导致制定了一种新的方法,该方法避免了吡咯与热或强酸性条件接触,从而避免了所需产物的分解。该方法包括将2,5-二甲氧基四氢呋喃在水中温和水解为活化的物质2,5-二羟基四氢呋喃,使其在室温下与乙酸酯缓冲液中的伯胺反应,以高收率得到N-取代的吡咯。在手性胺的情况下,吡咯的形成在没有可检测的差向异构的情况下进行。还可以高收率和高纯度获得对酸或热敏感的吡咯。