Catalytic Copper-Mediated Ring Opening and Functionalization of Benzoxazoles
Catalytic Copper-Mediated Ring Opening and Functionalization of Benzoxazoles
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DOI：
10.1021/cs5012519
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发表时间：
2014-11-01
期刊：
影响因子：
12.9
通讯作者：
Perez, Pedro J.
中科院分区：
文献类型：
--
作者：
Corro, Macarena;Besora, Maria;Perez, Pedro J.
以TP(Br3)Cu(NCMe)(TP(Br3)=氢三(3，4，5-三溴吡唑)硼酸盐)为催化剂，研究了苯并恶唑、重氮乙酸乙酯和水的反应。稠合的偶氮化合物被转化为含醛、羧酸胺和羟基的高度官能化的取代苯。该方法已应用于一系列含有几种重氮化合物的苯并恶唑类化合物。实验数据和理论计算已经导致了包括卡宾加成、叶立德形成和水加成在内的机理建议，所有这些步骤都是由铜中心催化的。
A novel reaction involving benzoxazole, ethyl diazoacetate, and water has been discovered, with Tp(Br3)Cu(NCMe) (Tp(Br3) = hydrotris(3,4,5-tribromopyrazolyl)borate) as the catalyst. The fused azoles are converted into highly functionalized substituted benzenes bearing aldehyde, amine carboxylate and hydroxyl groups. The protocol has been applied for a series of benzoxazoles with several diazo compounds. Experimental data and theoretical calculations have led to a mechanistic proposal that includes carbene addition, ylide formation, and water addition to the latter, all those steps being catalyzed by the copper center.