Formamides as Isocyanate Surrogates: A Mechanistically Driven Approach to the Development of Atom-Efficient, Selective Catalytic Syntheses of Ureas, Carbamates, and Heterocycles
Formamides as Isocyanate Surrogates: A Mechanistically Driven Approach to the Development of Atom-Efficient, Selective Catalytic Syntheses of Ureas, Carbamates, and Heterocycles
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DOI：
10.1021/jacs.9b08942
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发表时间：
2019-10-16
影响因子：
15
通讯作者：
Milstein, David
中科院分区：
文献类型：
--
作者：
Bruffaerts, Jeffrey;von Wolff, Niklas;Milstein, David
尽管异氰酸酯具有危险的性质，但它们仍然是大宗和精细化学合成的关键组成部分。通过用效力较低且容易获得的甲酰胺前体替代它们，我们在这里展示了一种替代的机械方法，通过基于Ru的钳形络合物催化的无受体脱氢偶联反应选择性地获得广泛的尿素、氨基甲酸酯和杂环。这些原子效率高的程序的设计是由相关有机金属络合物的鉴定和表征推动的，独特地展示了异氰酸酯中间体的捕获。密度泛函理论(DFT)的计算进一步阐明了涉及金属-配体合作的显著协调的催化事件链。
Despite the hazardous nature of isocyanates, they remain key building blocks in bulk and fine chemical synthesis. By surrogating them with less potent and readily available formamide precursors, we herein demonstrate an alternative, mechanistic approach to selectively access a broad range of ureas, carbamates, and heterocycles via ruthenium-based pincer complex catalyzed acceptorless dehydrogenative coupling reactions. The design of these highly atom-efficient procedures was driven by the identification and characterization of the relevant organometallic complexes, uniquely exhibiting the trapping of an isocyanate intermediate. Density functional theory (DFT) calculations further contributed to shed light on the remarkably orchestrated chain of catalytic events, involving metal-ligand cooperation.