The use of coordinating moieties as directing groups for the functionalization of aromatic CH bonds has become an established tool to enhance reactivity and induce regioselectivity. Nevertheless, with regard to the synthetic applicability of CH activation, there is a growing interest in transformations in which the directing group can be fully abandoned, thus allowing the direct functionalization of simple benzene derivatives. However, this approach requires the disclosure of new strategies to achieve reactivity and to control selectivity. In this review, recent advances in the emerging field of non-chelate-assisted CH activation are discussed, highlighting some of the most intriguing and inspiring examples of induction of reactivity and selectivity.

Beyond directing groups: transition-metal-catalyzed C-H activation of simple arenes.

Iron Catalysis in Organic Synthesis

Good Partnership between Sulfur and Fluorine: Sulfur-Based Fluorination and Fluoroalkylation Reagents for Organic Synthesis

Research and industrial interest in radical C–H activation/radical cross-coupling chemistry has continuously grown over the past few decades. These reactions offer fascinating and unconventional approaches toward connecting molecular fragments with high atom- and step-economy that are often complementary to traditional methods. Success in this area of research was made possible through the development of photocatalysis and first-row transition metal catalysis along with the use of peroxides as radical initiators. This Review provides a brief and concise overview of the current status and latest methodologies using radicals or radical cations as key intermediates produced via radical C–H activation. This Review includes radical addition, radical cascade cyclization, radical/radical cross-coupling, coupling of radicals with M–R groups, and coupling of radical cations with nucleophiles (Nu).

Recent Advances in Radical C-H Activation/Radical Cross-Coupling.

Oxidative Coupling between Two Hydrocarbons: An Update of Recent C–H Functionalizations

Copper- and iron-catalyzed decarboxylative tri- and difluoromethylation of α,β-unsaturated carboxylic acids with CF3SO2Na and (CF2HSO2)2Zn via a radical process.

Free-radical cascade alkylarylation of alkenes with simple alkanes: highly efficient access to oxindoles via selective (sp3)C-H and (sp2)C-H bond functionalization.

A free radical cascade cyclization of isocyanides with simple alkanes and alcohols.

A Free-Radical Cascade Trifluoromethylation/Cyclization of N-Arylmethacrylamides and Enynes with Sodium Trifluoromethanesulfinate and Iodine Pentoxide

Iodotrifluoromethylation of alkenes and alkynes with sodium trifluoromethanesulfinate and iodine pentoxide.

Zejiang Li

Papers

Copper- and iron-catalyzed decarboxylative tri- and difluoromethylation of α,β-unsaturated carboxylic acids with CF3SO2Na and (CF2HSO2)2Zn via a radical process.

Free-radical cascade alkylarylation of alkenes with simple alkanes: highly efficient access to oxindoles via selective (sp3)C-H and (sp2)C-H bond functionalization.

A free radical cascade cyclization of isocyanides with simple alkanes and alcohols.

A Free-Radical Cascade Trifluoromethylation/Cyclization of N-Arylmethacrylamides and Enynes with Sodium Trifluoromethanesulfinate and Iodine Pentoxide

Iodotrifluoromethylation of alkenes and alkynes with sodium trifluoromethanesulfinate and iodine pentoxide.