Carbon–Carbon Bond Activation by Group 9 Metal Complexes

Abstract

Activation of carbon–carbon bond with transition metal complexes in homogeneous conditions is an emerging field in chemical transformation. The numerous reports in last century have aided the understandings and realization of selective cleavage of carbon–carbon bond in organic molecules, from the viewpoints of the choice of metal, ligand design and substrate scopes. Specifically, this review focuses on the oxidative addition of C–C bond with group 9 transition metal complexes including the rational design from stoichiometric to catalytic transformation from the insight of carbon–carbon and metal‐carbon bond strengths.

Oxidative Coordination versus C3−C(O)Me Bond Cleavage in Acetylacetonate Iridium Complexes

“…Selective cleavage of C−H and C−C bonds represents a milestone in organometallic chemistry, and it is of great interest in the field of catalysis and organic synthesis, mainly for the functionalization of hydrocarbons [1–7] . Although, C−C bond activation is not thermodynamically preferred over C−H activation, the favorable formation of two M−C bonds by cleavage of a C−C bond can even lead to the rupture of strong C(sp 2 )−C(sp 2 ) bonds, especially with metals such as Rh and Ir [8] . To facilitate the C−C bond activation, at least two general strategies have been developed: i) Increasing the energy state of the starting materials, and ii) Lowering the energy state of the complex at which the C−C bond cleavage takes place [9] …”

HAT Catalysts to Facilitate Acid Mediated Cleavage of Biaryl C–C Bonds in Binaphthols

“…A ctivation of carbon−carbon (C−C) bonds has provided unique solutions to adding molecular complexity. 1,2 Numerous methods of C−C activation have been developed; however, most studies focus on polarized bonds such as C− CN or C−carbonyl bonds. 3−5 Historically, activation of nonpolarized bonds such as aryl−aryl C−C bonds has been challenging and often requires strained bonds such as those found in biphenylene.…”

“…Activation of carbon–carbon (C–C) bonds has provided unique solutions to adding molecular complexity. , Numerous methods of C–C activation have been developed; however, most studies focus on polarized bonds such as C–CN or C–carbonyl bonds. − Historically, activation of nonpolarized bonds such as aryl–aryl C–C bonds has been challenging and often requires strained bonds such as those found in biphenylene. , Methods for the activation of unstrained aryl–aryl bonds are desirable for the valorization of lignin. Lignin is a biopolymer found especially in trees and is a major waste product of the paper pulping industry, contributing to 10–50 million tons being produced annually, with much of it being burned as fuel .…”

Catalytic, Directed C–C Bond Functionalization of Styrenes

“…Transition-metal-catalyzed bond formation via cleavage of unstrained C–C single bonds has attracted increasing attention because such strategies would provide unconventional methods to synthesize complex organic molecules . There have been a large number of reports on unstrained C–C bond functionalization, but types of cleavable C–C bonds are still limited.…”

“…There have been a large number of reports on unstrained C–C bond functionalization, but types of cleavable C–C bonds are still limited. Namely, C–C bonds adjacent to polar groups such as cyano, carbonyl, imino, and hydroxy groups have been frequently targeted as the cleavage sites . In contrast, catalytic functionalization via cleavage of nonpolar C–C bonds is relatively unexplored. − …”