Synthesis of 4,5-Dihydroisoxazoles by Condensation of Primary Nitro Compounds with Alkenes by Using a Copper/Base Catalytic System
作者:Luca Cecchi、Francesco De Sarlo、Fabrizio Machetti
DOI:10.1002/chem.200800554
日期:2008.9.8
A new procedure for the synthesis of 4.5-dihydroisoxazoles by condensation of primary nitro compounds with olefins by using a copper/base catalytic system is described. The catalytic effect of copper(II) salts is evidenced by comparison of the reaction rates. Thus, activated nitro compounds react faster than with organic catalysis by tertiary amines, whereas nitroalkanes, unable to condense with dipolarophiles
描述了一种通过使用铜/碱催化体系将伯硝基化合物与烯烃缩合来合成4.5-二氢异恶唑的新方法。通过比较反应速率证明了铜(II)盐的催化作用。因此,活化的硝基化合物的反应要比叔胺的有机催化反应快,而仅在碱的存在下不能与双极性亲和剂缩合的硝基烷烃在加入铜(II)催化剂时会发生反应。在大多数反应中观察到的诱导期的出现归因于速率确定步骤之前的平衡,并暗示了拟议的反应机理。结果表明,该方法在合成实践中可能具有实用性和通用性。