Advances in the development of catalytic tethering directing groups for C–H functionalization reactions

Abstract

Transition metal-catalyzed C-H bond insertion is one of the most straightforward strategies to introduce functionalities within a hydrocarbon microenvironment. For the past two decades, selective activation and functionalization of certain inert C-H bonds have been made possible with the help of directing groups (DGs). Despite the enormous advances in the field, an overwhelming majority of systems require two extra steps from their simple precursors: installation and removal of the DGs. Recently, traceless and multitasking groups were invented as a partial solution to DG release. However, installation remains largely unsolved. Ideally, a transient, catalytic DG would circumvent this problem and increase the step- and atom-economy of C-H functionalization processes. In this review, we summarize the recent development of the transient tethering strategy for C-H activation reactions.

Enantioselective Synthesis of Atropisomers Featuring Pentatomic Heteroaromatics

“…7). [26,27] 以手性叔亮氨酸为瞬态手 性辅基, 先后实现了钯催化不对称碳氢键烯基化 [28a] 、 炔 基化 [28b] 和烯丙基化 [28c] , 成功实现了一系列轴手性联芳 基醛化合物高效合成. 这些轴手性联芳基醛主要集中在 一系列以 C-C 键为轴的六元联芳化合物, 如联苯和联 萘类等.…”

The use of carboxylic acids as traceless directing groups for regioselective C–H bond functionalisation

“…Although much progress has been made in the development of these directing groups, mainly through the reversible formation of phosphinite, imine or enamine functionalities, they still require a specific functionality on the molecule on which to tether. 10 An ideal situation would be to use a directing group inherent to a number of natural and commercially available compounds which can also be tracelessly removed. Within these specifications an attractive functionality is the carboxylate moiety.…”

Introducing the Chiral Transient Directing Group Strategy to Rhodium(III)‐Catalyzed Asymmetric C−H Activation

“…[3] Although great success has been achieved,t he most notable drawback associated with this strategym ight be having to pre-install DG beforehanda nd remove it after the reaction. [4] Encouragingly,t his problem is partially overcomeb yt he strategy of using at ransient directing group [5] (TDG)p ioneered by Juna nd co-workers, [6] in which the DG is installed (typically in as mall amount)a nd removed in situ automatically during the reaction process. Moreover,a s could be easily imagined, if ac hiral transientd irectingg roup is introduced, it is possible to achievea na symmetricc atalytic CÀ Ha ctivation reaction.…”