Transition-Metal-Catalyzed C–H Arylation Using Organoboron Reagents

Abstract

Aryl rings are frequently found at the core of numerous omnipresent molecules and facile synthesis of these microscopic grains is of major interest in the scientific community and industry. Although multiple strategies enable access to those skeletons, the inclusion of metal-catalyzed C-H activation makes it most promising due to its remarkable efficiency. Commercially available organoborons, a prominent arylating partner in the cross-coupling domain, have transcended to the direct arylation segment as well. Decent stability of these reagents helps in avoiding delicate conditions, assuring regioselectivity, chemodivergence, cost-efficiency, and atom-economy. This critical, concise review presents a summary of all major studies of arylation using organoborons in transition metal catalysis, communicated within the 15 years.

Molecular engineering of 3-arylated tetrazo[1,2-b]indazoles: divergent synthesis and structure–property relationships

“…8,13 We then extended our C-H activation toolbox by exploring the use of other transition metals. Based on the abilities of rhodium and iridium in the N-directed oxidative cross-coupling functionalization, 14,15 the direct (hetero)arylation of the 3- (2-fluorophenyl)-tetrazo[1,2-b]indazole 17 was demonstrated in two oxidative cross-coupling reactions (Scheme 8). These reactions took place with [Cu(OAc) 2 ] as the oxidant in dichloroethane (DCE) at 140 °C.…”

Future prospects in boron chemistry: new boron compounds and Lewis acids for catalysis and materials science

“…Very recently, N-heterocyclic carbene-stabilized o-carboranyl-substituted borenium ions were used for the very first transition metal-free C-H bond activation and borylation of methane and longer alkanes [Figure 3C] [51] , and frustrated Lewis pairs constituted by weakly coordinating anion and pyramidal boron Lewis superacids were used for the C-H bond activation and borylation of unactivated arenes and for their subsequent conversion to fluoroaromatics [Figure 3D] [52] . Thus, highly electron-deficient boron Lewis acids will likely be employed in the near future for the catalytic borylation, silylation and functionalization of hydrocarbons and for their subsequent functionalization.…”

Chemo-, regio- and stereoselective access to polysubstituted 1,3-dienes via Nickel-catalyzed four-component reactions

“…In the past decade, the development of various coupling partners greatly increases organic molecular complexity and facilitates reaction diversification 13 , 16 , 17 . Among them, organoboron reagents are attractive and valuable synthons owing to their air stability, non-toxicity, abundance, readily accessible, and broad availability in versatile transformations 13 , 18 – 20 . Hence, transition-metal-catalyzed 1,2-difunctionalization of alkynes involving organoboron reagents 13 , 17 , 21 has been proven to be one of the most versatile and powerful tools for the efficient construction of diverse chemical bonds recently.…”