Efficient and Selective Room-Temperature Gold-Catalyzed Reduction of Nitro Compounds with CO and H2O as the Hydrogen Source
Efficient and Selective Room-Temperature Gold-Catalyzed Reduction of Nitro Compounds with CO and H2O as the Hydrogen Source
复制标题
以 CO 和 H2O 为氢源的金催化室温高效选择性还原硝基化合物
DOI：
10.1002/anie.200904647
复制
发表时间：
2009-01-01
影响因子：
16.6
通讯作者：
Ean, Kang-Nian
中科院分区：
文献类型：
--
作者：
He, Lin;Wang, Lu-Cun;Ean, Kang-Nian
硝基化合物选择性还原为相应的胺是合成有机化学中最重要的转化之一虽然已经开发了许多方法，但寻找新的简便、化学选择性、成本效益和环境友好的方法，以避免大量使用昂贵和危险的化学计量还原剂，已经引起了人们的极大兴趣一个有吸引力的替代方案是用廉价和容易获得的CO和H2O作为氢源催化还原硝基化合物。特别是，在存在其他官能团的温和条件下，硝基的特异性还原是可取的。与常用的以H2为还原剂的催化加氢不同，以CO和H2O为氢源的催化加氢具有显著的化学选择性，具有很大的工业潜力，特别是当可以采用高效且可重复使用的催化体系时。然而，相关研究主要集中在各种基于钌或铑的均相体系，[5]由于其周转量（吨）和周转率（tfs）低，并且需要大量过量的有机和/或无机碱作为助催化剂而没有实际用途。尽管在过去的二十年中付出了巨大的努力，但以CO/H2O为还原剂还原硝基化合物的多相催化剂体系很少出现，而且这些体系通常存在效率低、底物范围有限和催化剂可重复使用的问题。由于其独特的温和条件下的催化性能，负载型金纳米颗粒已成为广泛的有机反应的活性和极选择性催化剂虽然金催化的选择性氧化反应在原子经济和可持续有机合成方面的潜力已得到广泛认可，但在负载金的催化还原中提供的可能性更大
The selective reduction of nitro compounds to the corresponding amines is one of the most important transformations in synthetic organic chemistry.[1] Although a number of methods have been developed, the search for new facile, chemoselective, cost-effective, and environmentally friendly procedures that avoid the use of expensive and hazardous stoichiometric reducing agents in large excess has attracted substantial interest.[2] An attractive alternative is the catalytic reduction of nitro compounds with cheap and readily available CO and H2O as the hydrogen source. In particular, the specific reduction of a nitro group under mild conditions in the presence of other functionalities is desirable. As opposed to commonly used catalytic hydrogenation, which involves H2 as the reductant,[3] the use of CO and H2O as the hydrogen source leads to remarkable chemoselectivity and is of great industrial potential,[4] especially when an efficient and reusable catalytic system can be employed. However, relevant studies have largely focused on various ruthenium-or rhodium-based homogeneous systems,[5] which are not practically useful because of their low turnover numbers (TONs) and turnover frequencies (TOFs), and the requirement of organic and/or inorganic bases in large excess as cocatalysts. Despite tremendous efforts in the last two decades,[6] few examples of heterogeneous catalyst systems for the reduction of a nitro compounds with CO/H2O as the reductant have appeared, and these systems have often suffered from low efficiency as well as limited substrate scope and catalyst reusability.Supported gold nanoparticles have emerged as active and extremely selective catalysts for a broad array of organic reactions owing to their unique catalytic properties under mild conditions.[7] Whereas the potential of gold-catalyzed selective oxidation reactions for atom-economical and sustainable organic synthesis is widely recognized,[8] the possibilities offered by catalytic reduction with supported gold