Carbon dioxide is a nontoxic, renewable, and abundant C1 source, whereas C−H bond functionalization represents one of the most important approaches to the construction of carbon–carbon bonds and carbon–heteroatom bonds in an atom‐ and step‐economical manner. Combining the chemical transformation of CO2 with C−H bond functionalization is of great importance in the synthesis of carboxylic acids and their derivatives. The contents of this Review are organized according to the type of C−H bond involved in carboxylation. The primary types of C−H bonds are as follows: C(sp)−H bonds of terminal alkynes, C(sp2)−H bonds of (hetero)arenes, vinylic C(sp2)−H bonds, the ipso‐C(sp2)−H bonds of the diazo group, aldehyde C(sp2)−H bonds, α‐C(sp3)−H bonds of the carbonyl group, γ‐C(sp3)−H bonds of the carbonyl group, C(sp3)−H bonds adjacent to nitrogen atoms, C(sp3)−H bonds of o‐alkyl phenyl ketones, allylic C(sp3)−H bonds, C(sp3)−H bonds of methane, and C(sp3)−H bonds of halogenated aliphatic hydrocarbons. In addition, multicomponent reactions, tandem reactions, and key theoretical studies related to the carboxylation of C−H bonds are briefly summarized. Transition‐metal‐free, organocatalytic, electrochemical, and light‐driven methods are highlighted.

Herein we report a general electrochemical strategy for the Sandmeyer reaction.

We describe an operationally simple transition-metal-free borylation of alkyl iodides. This method uses commercially available diboron reagents as the boron source and exhibits excellent functional group compatibility. Furthermore, a diverse range of primary and secondary alkyl iodides could be effectively transformed to the corresponding alkylboronates in excellent yield. Mechanistic investigations suggest that this borylation reaction proceeds through a single-electron transfer mechanism featuring the generation of an alkyl radical intermediate.

We describe here an operationally simple and straightforward synthesis method for a series of diverse 4,5-disubstituted 1,2,3-thiadiazoles via the nucleophilic addition of α-diazo carbonyl compounds to carbon disulfide. This method features using abundant and inexpensive carbon disulfide under mild reaction conditions.

We report an operationally simple and neutral conditions for borylation of alkyl bromides and iodides to alkyl boronic esters under transition metal- and photo-free conditions. A series of substrates with...

The borylation of unreactive carbon-hydrogen bonds is a valuable method for transforming feedstock chemicals into versatile building blocks. Here, we describe a transition metal-free method for the photoredox-catalyzed borylation of unactivated C(sp3)−H bond, initiated by 1,5-hydrogen atom transfer (HAT). The remote borylation was directed by 1,5-HAT of the amidyl radical, which was generated by photocatalytic reduction of hydroxamic acid derivatives. The method accommodates substrates with primary, secondary and tertiary C(sp3)−H bonds, yielding moderate to good product yields (up to 92%) with tolerance for various functional groups. Mechanistic studies, including radical clock experiments and DFT calculations, provided detailed insight into the 1,5-HAT borylation process.

The carboxylation of the C−H bond utilizing CO2 represents a challenging but attractive tactic for capitalizing on the abundant availability of CO2 in organic synthesis. In this investigation, we report...

We describe a transition-metal free, photoredox-catalyzed borylation method of unactivated C(sp3)-H bonds via initiated 1,5-hydrogen atom transfer (HAT). The remote borylation was directed by 1,5-HAT of the amidyl radical, which was generated by photocatalytic reduction of hydroxamic acid derivatives. Substrates bearing primary, secondary and tertiary C(sp3)-H bonds could all be accommodated in this remote borylation protocol, giving moderate to good yields of the desired products (up to 92%), and a series of functional groups were tolerated. Mechanistic studies, including radical clock experiments and DFT calculations, gave detailed insight into the 1,5-HAT borylation process.