Nickel‐Catalyzed Suzuki‐Miyaura Cross‐Coupling Involving C−O Bond Activation

Abstract

An efficient Suzuki‐Miyaura cross‐coupling reaction of ortho‐phenoxy‐substituted aromatic amides with aryl boronates is described. The use of LiOtBu is crucial for the success of the reaction. An amidate anion, which is formed through deprotonation of the amide NH bond by LiOtBu, functions as a directing group to activate a C−O bond.

Nickel-Catalyzed Functionalization Reactions Involving C–H Bond Activation via an Amidate-Promoted Strategy and Its Extension to the Activation of C–F, C–O, C–S, and C–CN Bonds

“…Similar to C–H bond activation, C–O bond activation has also received much attention in connection with the effective utilization of biomass, including lignin . We were pleased to find that the amidate-promoted strategy is also applicable to the activation of C–O bonds when a phenoxy group is used as a leaving group (Scheme A) . Unfortunately, a methoxy group (a poor leaving group) did not react.…”

Mechanistic Insight into Rh-Catalyzed C(sp2)–O Bond Cleavage Applied to Cross-Coupling Reaction of Benzofurans with Aryl Grignard Reagents

“…Although the pioneering work by Wenkert et al in 1979 on the Ni-catalyzed Kumada–Tamao–Corriu-type cross-coupling of alkenyl and aryl ethers with Grignard reagents exemplified the C–O bond cleavage of simple ethers, the yields were not always satisfactory . In the last 15 years, cross-coupling reaction of ethereal compounds with organometallic reagents via C­(sp 2 )–O bond cleavage has been developed using Ni, − Cr, Fe, Ru, and Rh as the catalysts, although the use of directing groups for C–O bonds cleavage was necessary in some cases. ,, …”

“…Among the transition-metal catalysts employed for the transformations of ethereal C–O bonds, Ni catalysts have attracted significant attention, because of their compatibility with various coupling partners, including organomagnesium, organolithium, organoboron, organoaluminum, and organozinc reagents (Scheme A). In these reactions, Ni catalysts usually exhibit appreciable reactivity toward π-extended anisole derivatives such as methoxynaphthalenes but are often less reactive toward simple anisoles.…”