Conversion of amides to esters by the nickel-catalysed activation of amide C–N bonds
作者:Liana Hie、Noah F. Fine Nathel、Tejas K. Shah、Emma L. Baker、Xin Hong、Yun-Fang Yang、Peng Liu、K. N. Houk、Neil K. Garg
DOI:10.1038/nature14615
日期:2015.8
Although enzymes are able to cleave amide bonds in nature, it is difficult to selectively break the carbonânitrogen bond of an amide using synthetic chemistry; now the activation and cleavage of these bonds using nickel catalysts is used to convert amides to esters. Although enzymes are able to cleave amide bonds in nature, it is difficult to selectively break the carbonânitrogen bond of an amide using synthetic chemistry. In this paper the authors demonstrate that amide CâN bonds can be activated and cleaved using nickel catalysts. They used this methodology to convert amides to esters, which is a challenging and underdeveloped transformation. Amides are common functional groups that have been studied for more than a century1. They are the key building blocks of proteins and are present in a broad range of other natural and synthetic compounds. Amides are known to be poor electrophiles, which is typically attributed to the resonance stability of the amide bond1,2. Although amides can readily be cleaved by enzymes such as proteases3, it is difficult to selectively break the carbonânitrogen bond of an amide using synthetic chemistry. Here we demonstrate that amide carbonânitrogen bonds can be activated and cleaved using nickel catalysts. We use this methodology to convert amides to esters, which is a challenging and underdeveloped transformation. The reaction methodology proceeds under exceptionally mild reaction conditions, and avoids the use of a large excess of an alcohol nucleophile. Density functional theory calculations provide insight into the thermodynamics and catalytic cycle of the amide-to-ester transformation. Our results provide a way to harness amide functional groups as synthetic building blocks and are expected to lead to the further use of amides in the construction of carbonâheteroatom or carbonâcarbon bonds using non-precious-metal catalysis.
尽管酶能够在自然界中断裂酰胺键,但利用合成化学选择性地打破酰胺的碳—氮键却很困难;现在,使用镍催化剂激活和断裂这些键被用于将酰胺转化为酯。本文作者证明,酰胺C—N键可以使用镍催化剂激活和断裂。他们利用这种方法将酰胺转化为酯,这是一种具有挑战性且发展不足的转化。酰胺是一类常见的官能团,一个多世纪以来一直被研究。它们是蛋白质的关键构建模块,存在于广泛的天然和合成化合物中。酰胺被认为是一种差的亲电试剂,这通常归因于酰胺键的共振稳定性。尽管酶如蛋白酶可以轻易地断裂酰胺,但利用合成化学选择性地打破酰胺的碳—氮键却很困难。在这里,我们证明酰胺碳—氮键可以使用镍催化剂激活和断裂。我们利用这种方法将酰胺转化为酯,这是一种具有挑战性且发展不足的转化。反应方法在极其温和的反应条件下进行,并避免了使用大量过量的醇亲核试剂。密度泛函理论计算为酰胺到酯转化的热力学和催化循环提供了见解。我们的结果为利用酰胺官能团作为合成构建块提供了一种方法,并有望进一步在非贵金属催化的碳—杂原子或碳—碳键构建中使用酰胺。