Carboxylation of N-H/C-H Bonds Using N-Heterocyclic Carbene Copper(I) Complexes
Carboxylation of N-H/C-H Bonds Using N-Heterocyclic Carbene Copper(I) Complexes
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DOI：
10.1002/anie.201004153
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发表时间：
2010-01-01
影响因子：
16.6
通讯作者：
Nolan, Steven P.
中科院分区：
文献类型：
--
作者：
Boogaerts, Ine I. F.;Fortman, George C.;Nolan, Steven P.
过渡金属介导的N±H和C±H键的羧化反应是有机化学中的一个新领域，因为这些反应可以有效地构建有价值的合成子。[1]钯催化的N-羰化-氧化序列是有很好记录的，但它们通常需要很高的催化剂负载量和使用气态一氧化碳或第六族金属-羰基配合物。[2]在强制温度下，钼和钨的羰基胺物种也促进了类似的转化序列。[3]使用Ru[1a]和镍的配合物在C-羧化反应中取得了重要的进展；[4]然而，在温和的条件下，例子很少。烯丙基锡烷、[5]有机锌、[6]和有机硼酸酯的羧化反应已被描述为一种提高官能团耐受性的新方法，但有机金属试剂的化学计量消耗仍然是一个缺点。烯丙基锡烷和有机锌化合物的反应性需要在惰性气氛下处理，而有机硼酸酯价格昂贵。最近开发了一种在非常温和的反应条件下对简单芳香族基团进行C-羧化反应的方案。在这种情况下，使用了含有N-杂环卡宾(NHC)配体[11]的强碱性[Au(Ipr)(OH)][9](ipr=1，3-二(二异丙基)苯基咪唑-2-亚甲基[10])络合物(PKA DMSO=30.3(2))。
Transition-metal-mediated carboxylation of NÀH and CÀH bonds represents a nascent area in organic chemistry, because these reactions enable the efficient construction of valuable synthons.[1] Palladium-catalyzed N-carbonylation–oxidation sequences are well-documented, but they often require high catalyst loadings and the use of either gaseous carbon monoxide or GroupVI metal–carbonyl complexes.[2] An analogous transformation sequence is also promoted by molybdenum and tungsten carbonyl amine species under forcing temperatures.[3] Important advances in C-carboxylation reactions have been made using ruthenium [1a] and nickel complexes;[4] however, examples under mild conditions are elusive. The carboxylation of allylstannanes,[5] organozincs,[6] and organoboronic esters [7, 8] have been described as a new method to improve functional group tolerance, but the stoichiometric consumption of an organometallic reagent remains a disadvantage. The reactivity of allylstannanes and organozinc compounds necessitates handling under an inert atmosphere, while organoboronic esters are expensive. A protocol has recently been developed for the C-carboxylation of simple aromatic groups under very mild reaction conditions. In this case the strongly basic [Au (IPr)(OH)][9](IPr= 1, 3-bis (diisopropyl) phenylimidazol-2-ylidene [10]) complex (pKa DMSO= 30.3 (2)) was used,[11] which contains an N-heterocyclic carbene (NHC) ligand [Eq.(1)].