A Highly Efficient Gold-Catalyzed Oxidative C?C Coupling from C?H Bonds Using Air as Oxidant
A Highly Efficient Gold-Catalyzed Oxidative C?C Coupling from C?H Bonds Using Air as Oxidant
复制标题
以空气为氧化剂的高效金催化 C?H 键氧化 C?C 偶联反应
DOI：
10.1002/anie.201107605
复制
发表时间：
2012-01-01
影响因子：
16.6
通讯作者：
Zhu, Chengjian
中科院分区：
文献类型：
--
作者：
Xie, Jin;Li, Huamin;Zhu, Chengjian
The construction of CÀC bond is a perennial subject of interest for the synthetic chemist. Lately, the homogeneous gold-catalyzed CÀC coupling reaction has emerged as a powerful method for the synthesis of intricate scaffolds.[1] In the methods reported, the introduction of a highly functionalized group or a sacrificial external oxidant was usually required, thus diminishing the overall sustainability of the gold-catalyzed process. In recent years, the direct use of two CÀH bonds for CÀC coupling has become a promising strategy, as CÀH bonds are ubiquitous in organic molecules.[2] In 2009 and 2010, the groups of Tse and Nevado reported the gold-catalyzed oxidative homocoupling of simple arenes and oxidative ethynylation of arenes with terminal alkynes using PhI (OAc) 2 as an oxidant.[3] However, the gold-catalyzed oxidative CÀC coupling of Csp3ÀH bonds under aerobic oxidative conditions is still a challenge.[4–5] Directed toward such goals, we became interested in the gold-catalyzed oxidative CÀC coupling of amines with various Csp3ÀH coupling partners. Although some notable progress has been achieved in this area, a stoichiometric amount of dangerous oxidants or pure oxygen (! 1.0 atm), and even specialized reaction conditions are usually necessary.[6, 7] These disadvantages have seriously limited the utility of such methods. Therefore, the development of a more environmentally benign and convenient catalytic system for amine functionalization is highly desirable. Following the principle of sustainable chemistry, air is a favorable oxidant, with water as the only waste product, and it has received considerable attention in modern oxidation chemistry.[8] To the best of our knowledge, there is no successful example of a gold-catalyzed α-CÀH functionalization of amines using air as the sole oxidant.[5, 9] Herein, we wish to report an unprecedented homogeneous gold-catalyzed amine functionalization protocol involving the oxidative CÀC coupling of two different CÀ H bonds with air as a sustainable and efficient oxidant.In our initial study, the oxidative CÀC coupling reaction of N-phenyl tetrahydroisoquinoline 7a with nitromethane 8a was chosen as a model reaction.[10] The results are summarized in Table 1. To our delight, the aerobic oxidative CÀC coupling reaction could occur under the catalysis of 1a
