Organometallic C—H Bond Activation: An Introduction

Abstract

An introduction to the field of activation and fimctionalization of C-H bonds by solution-phase transition -metal-based systems is presented, with an emphasis on the activation of aliphatic C-H bonds. The focus of this chapter is on stoichiometric and catalytic reactions that operate via organometallic mechanisms, i.e., those in which a bond is formed between the metal center and the carbon undergoing reactionThe carbon-hydrogen bond is the un-functional group. Its unique position in organic chemistry is well illustrated by the standard representation of organic molecules: the presence of C-H bonds is indicated simply by the absence of any other bond. This "invisibility" of C-H bonds reflects both their ubiquitous nature and their lack of reactivity. With these characteristics in mind it is clear that if the ability to selectively fiinctionalize C-H bonds were well developed, it could potentially constitute the most broadly applicable and powerful class of transformations in organic synthesis. Realization of such potential could revolutionize the synthesis of organic molecules ranging in complexity from methanol to the most elaborate natural or unnatural products.The following chapters in this volume offer a view of many of the current leading research efforts in this field, in particular those focused on the activation

CH Bond Functionalization through Intramolecular Hydride Transfer

“…Goldberg and Goldman have termed the CÀH bond "the un-functional group," highlighting its privileged status both as a tool for synthesis and as a target for methodology. [1] Many noteworthy examples of C À H functionalization can be classified as oxidative, including the classic work of Shilov and Fujiwara. [2,3] More recent work has brought forth advances in photoredox catalysis, [4] processes where molecular oxygen serves as the terminal oxidant, [5] and site-selective transition-metal-catalyzed CÀH oxygenation.…”

Surface Transformation of Spin-on-Carbon Film via Forming Carbon Iron Complex for Remarkably Enhanced Polishing Rate

“…Afterwards, two dehydrated =C- bonds (i.e., carbon radicals) were attached to O atoms, producing C-O bonds on the SOC film surface with 286.9 and 531.2 eV in binding energy, as shown in b and c of Figure 6 b. Third, Fe atoms were inserted into C-H bonds on the SOC film surface via an oxidative addition reaction, as shown in a and b of Figure 6 c [ 31 , 32 , 33 , 34 , 35 ]. The second C–H bond additions were located at the adjacent C–H bonds, known as β-hydrogen elimination, as shown in b and c of Figure 6 c [ 36 ].…”

Metal-Catalyzed Cross-Coupling Reactions on Azaindole Synthesis and Functionalization

“…This reaction constitutes a great advance in metal-catalysis, however there are still some challenges, such as the regioselectivity [ 28 ] (C–H sp2 and sp3 bonds are ubiquous), the low reactivity due to a great energy barrier to break a C–H bond (104 kcal/mol) and at last the chemoselectivity [ 29 , 30 ].…”