Unlocking the Nucleophilicity of Strong Alkyl C-H Bonds via Cu/Cr Catalysis

Thiobenzoic Acid-Catalyzed Cα-H Cross Coupling of Benzyl Alcohols with α-Ketoacid Derivatives

The C-H alkylation of benzyl alcohols with α-ketoacid derivatives was achieved in the presence of thiobenzoic acid with or without Ru or Ir photoredox catalysts. The thiobenzoic acid serves as a photoexcited single-electron reducing reagent and a hydrogen atom transfer catalyst, while addition of the metal photoredox catalyst assists the electron transfer and improves the reaction efficiency. Various functional groups were tolerant of the reaction conditions, and sterically hindered diols were produced in good to high yield.

Photoelectrochemical Fe/Ni cocatalyzed C-C functionalization of alcohols

The simultaneous activation of reactants on the anode and cathode via paired electrocatalysis has not been extensively demonstrated. This report presents a paired oxidative and reductive catalysis based on earth-abundant iron/nickel cocatalyzed C-C functionalization of ubiquitous alcohols. A variety of alcohols (i.e., primary, secondary, tertiary, or unstrained cyclic alcohols) can be activated at very low oxidation potential of (~0.30 V vs. Ag/AgCl) via photoelectrocatalysis coupled with versatile electrophiles. This reactivity yields a wide range of structurally diverse molecules with broad functional group compatibility (more than 50 examples).

Construction of indolizine scaffolds from α,ω-alkynoic acids and α,ω-vinylamines via sequential-relay catalysis in "one pot"

A simple and efficient method has been developed for the synthesis of a diverse range of aryl-fused indolizin-3-ones through sequential Au(I)-catalyzed hydrocarboxylation, aminolysis, and cyclization, followed by ruthenium-catalyzed ring-closing metathesis. Moderate to good yields were observed with satisfactory substrate scope and functional group tolerance. The developed protocol represents a practical strategy for the construction of bioactive aryl-fused indolizin-3-ones.

1,3-Butadiene Dicarbofunctionalization Enabled by the Dual Role of Diaryl Ketone in Photo-HAT/Chromium Catalysis

We report a three-component Nozaki-Hiyama-Kishi type reaction of 1,3-dioxolane, 1,3-butadienes, and aldehydes to access masked aldehyde-incorporated homoallylic alcohols, facilitated by photo-hydrogen atom transfer (HAT)/chromium dual catalysis. The diaryl ketone serves dual roles both in the HAT process and in facilitating the turnover of the chromium catalyst. A range of functional groups are tolerated owing to the mild conditions. Both aromatic and aliphatic aldehydes are suitable substrates for coupling with several 1,3-butadienes and 1,3-dioxolane.

Photo-induced versatile aliphatic C-H functionalization via electron donor-acceptor complex

The ability to selectively introduce diverse functionality onto hydrocarbons is of substantial value in the synthesis of both small molecules and pharmaceuticals. In this endeavour, as a photocatalyst- and metal-free process, the electron donor-acceptor (EDA) strategy has not been well explored. Here we report an approach to aliphatic carbon-hydrogen bond diversification through an EDA complex constituted by HCl and SIV=O groups. As an efficient hydrogen atom transfer (HAT) reagent, chlorine radical can be produced via a proton-coupled electron transfer process in this system. Based on this unusual path, a photo-promoted versatile aliphatic C-H functionalization is developed without photo- and metal-catalysts, including thiolation, arylation, alkynylation, and allylation. This conversion has concise and ambient reaction conditions, good functional group tolerance, and substrate diversity, and provides an alternative solution for the high value-added utilization of bulk light alkanes.

Manganese/Cobalt Bimetallic Relay Catalysis for Divergent Dehydrogenative Difluoroalkylation of Alkenes

The involvement of manganese radical for halogen atom transfer (XAT) reactions has been esteemed as one reliable method but encountered with limited catalytic models. In this paper, a novel bimetallic relay catalysis of Mn2 (CO)10 and cobaloxime has been developed for divergent dehydrogenative difluoroalkylation of alkenes using commercially available difluoroalkyl bromides. A wide range of structurally diverse terminal, cyclic and internal alkenes as well as tetrasubstituted alkenes are found to be good coupling partners to deliver difluoroalkylated allylic products and difluoromethylated cyclic products, accompanied with the production of H2 as the by-product. This bimetallic relay strategy features broad substrate scope, mild reaction conditions and excellent functional group compatibility. Its success represents an important step-forward to expedite the construction of a rich library of difluoroalkylated products.