镍催化惰性碳氢键活化研究进展

Recent progress on nickel-catalyzed direct functionalization of unactivated C–H bonds

相较于传统的偶联反应,碳氢键活化由于无需预官能团化,而具有相对更高的原子经济性和环境友好性,近年来广受关注,并取得迅猛发展.钯、铑、钌和铱等贵金属催化的碳氢键活化近年来已经取得了令人瞩目的发展,但较高的催化剂成本以及有毒有害的重金属残留在一定程度上也限制了其应用.因此,以储量丰富并且价格相对低廉的铁、钴、镍和铜等廉价金属为催化剂,实现惰性碳氢键活化具有重要的科学价值和经济意义.由于镍催化剂价格相对低廉并且具有良好的催化活性,近年来,镍催化的惰性碳氢键活化受到广泛关注.本文综述了镍催化的惰性碳氢键活化的最新研究进展,并对催化体系、成键类型和反应机理进行了初步探讨.

Over the past few decades, transition-metal catalyzed direct functionalization of unactivated C-H bonds has emerged as an efficient and straightforward strategy for the construction of C-C and C-heteroatom bonds. It provides access to complex molecules via the direct cleavage of C-H bonds without the need of prefunctionalization, rendering this strategy more step-economical and environmentally benign. Recently, tremendous attentions have been devoted to the use of first row-transition metals as most of those metals are naturally abundant, readily available, and inexpensive and have low toxicities in comparison with precious metals. In addition, the exploration of new catalytic systems might lead to the discovery of new mode of reactions. The aim of this review is to give an overview on recent advances in nickel-catalyzed direct functionalization of unactivated C-H bonds, without the discussion of the cleavage of acidic C-H bonds. Firstly, nickel-catalyzed functionalization of C（spZ）-H to form new C--C and C-heteroatom bonds is reviewed. Secondly, an overview of Ni-catalyzed C（sp3）-H functionalization is provided. In addition, mechanistic hypothesis and general aspects of these reactions have also been summarized. Finally, the limitations and perspectives on nickel-catalyzed C-H functionalization are discussed.