Visible-Light-Mediated Vicinal Dihalogenation of Unsaturated C-C Bonds Using Dual-Functional Group Transfer Reagents.

The growing demand for chemical production continues to drive the development of sustainable and efficient methods for introducing molecular complexity. In this context, the exploration of unconventional functional group transfer reagents (FGTRs) has led to significant advancements in practical and atom-efficient synthetic protocols. Aiming to advance the field of valuable organic synthesis, herein we report the successful development of carbon-based, bench-stable, modular, and inexpensive reagents implemented in dual halogen transfer to unsaturated hydrocarbons via photocatalytic activation of reagents based on a radical-polar crossover mechanism.

Divergent functionalization of alkenes enabled by photoredox activation of CDFA and α-halo carboxylic acids.

Herein we present our studies on the solvent-controlled difunctionalization of alkenes utilizing chlorodifluoroacetic acid (CDFA) and α-halo carboxylic acids for the synthesis of γ-lactones, γ-lactams and α,α-difluoroesters. Mechanistic insights revealed that photocatalytic reductive mesolytic cleavage of the C-X bond delivers elusive α-carboxyl alkyl radicals. In the presence of an olefin molecule, this species acts as a unique bifunctional intermediate allowing for stipulated formation of C-O, C-N and C-H bonds on Giese-type adducts single electron transfer (SET) or hydrogen atom transfer (HAT) events.

Review and Theoretical Analysis of Fluorinated Radicals in Direct C-H Functionalization of (Hetero)arenes.

We highlight key contributions in the field of direct radical C- H (hetero)aromatic functionalization involving fluorinated radicals. A compilation of Functional Group Transfer Reagents and their diverse activation mechanisms leading to the release of radicals are discussed. The substrate scope for each radical is analyzed and classified into three categories according to the electronic properties of the substrates.

Electron-Driven Nitration of Unsaturated Hydrocarbons.

Herein, we introduce an electrochemically assisted generation of nitryl radicals from ferric nitrate under mild reaction conditions using a simple setup with inexpensive graphite and stainless-steel electrodes. The mechanism of the reaction is supported by detailed spectroscopic and experimental studies. Powered by electricity and driven by electrons, the synthetic diversity of this reaction has been demonstrated through the development of highly efficient nitration protocols of various unsaturated hydrocarbons.

Photoredox Activation of Anhydrides for the Solvent-Controlled Switchable Synthesis of gem-Difluoro Compounds.

The incorporation of the gem-difluoromethylene (CF ) group into organic frameworks is highly sought due to the influence of this unit on the physicochemical and pharmacological properties of molecules. Herein we report an operationally simple, mild, and switchable protocol to access various gem-difluoro compounds that employs chlorodifloroacetic anhydride (CDFAA) as a low-cost and versatile fluoroalkylating reagent. Detailed mechanistic studies revealed that electron-transfer photocatalysis triggers mesolytic cleavage of a C-Cl bond generating a gem-difluoroalkyl radical.