Deuterium- and Electron-Shuttling Catalysis for Deoxygenative Deuteration of Alcohols.

A practical and precise method for visible-light-promoted deoxygenative deuteration of common aliphatic alcohols using D2O as the deuterium source is reported. Upon intermediacy of xanthate anions, a variety of primary, secondary, and tertiary alcohols can be facilely transformed into deuterioalkanes with excellent D-incorporation at predicted sites. The deoxygenation and deuteration sequence is catalyzed by in situ formed deuterated 2-mercaptopyridine, which plays dual roles as a deuterium atom transfer catalyst and an electron shuttle as well.

Direct Photoexcitation of Xanthate Anions for Deoxygenative Alkenylation of Alcohols.

In this report, we identify xanthate salts as a unique class of visible-light-excitable alkyl radical precursors that act simultaneously as strong photoreductants and alkyl radical sources. Upon direct photoexcitation of xanthate anions, efficient deoxygenative alkenylation and alkylation of a wide range of primary, secondary, and tertiary alcohols have been achieved via a one-pot protocol, avoiding any photocatalysts. This method exhibits a broad substrate scope and good functional group tolerance, enabling late-stage functionalization of complex molecules.

Radical C-C Bond Cleavage/Addition Cascade of Benzyl Cycloketone Oxime Ethers Enabled by Photogenerated Cyclic Iminyl Radicals.

A light-driven, metal-free, and iminyl radical-mediated ring-opening C-C bond cleavage/addition cascade of O-4-methoxybenzyl oxime ethers and alkenes is described for the first time. The reaction shows a broad substrate scope and high functional group compatibility with both components, giving the corresponding valuable oxo nitriles in generally good yields. Key to the success of this protocol is the generation of cyclic iminyl radicals from the O-4-methoxybenzyl oxime ethers via a photocatalytic hydrogen atom transfer (HAT) process. The proposed main pathway is also supported by the preliminary mechanistic studies.

Photoinduced, Copper-Catalyzed Radical Cross-Coupling of Cycloketone Oxime Esters, Alkenes, and Terminal Alkynes.

A photoinduced, copper-catalyzed three-component radical cross-coupling of cycloketone oxime esters, alkenes, and terminal alkynes is described for the first time. Key to the success of this process was the integration of photoinduced iminyl radical-mediated C-C bond cleavage with the conceptual simplicity of copper-catalyzed radical cross-coupling. This protocol provides access to cyanoalkyl-containing propargylic compounds in good yields.

A photoredox catalyzed iminyl radical-triggered C-C bond cleavage/addition/Kornblum oxidation cascade of oxime esters and styrenes: synthesis of ketonitriles.

A photoredox-catalyzed iminyl radical-triggered C-C bond cleavage/addition/Kornblum oxidation cascade of cycloketone oxime esters and styrenes in DMSO is described. This three-component, one-pot procedure features mild conditions, a broad substrate scope, and high functional group tolerance, providing an efficient approach to access diversely functionalized ketonitriles.

A photocatalytic iminyl radical-mediated C-C bond cleavage/addition/cyclization cascade for the synthesis of 1,2,3,4-tetrahydrophenanthrenes.

On the basis of the strategy of iminyl radical-mediated C-C bond cleavage, a visible light photocatalytic radical addition/cyclization cascade is described, providing an efficient and regioselective access to cyanoalkylated 1,2,3,4-tetrahydrophenanthrenes.

Umpolung of Imines Enables Catalytic Asymmetric Regio-reversed [3+2] Cycloadditions of Iminoesters with Nitroolefins.

A copper-catalyzed regio-reversed asymmetric [3+2] cycloaddition of iminoesters with nitroolefins is disclosed for the first time. This method enables the facile synthesis of polysubstituted chiral pyrrolidines bearing at least one chiral quaternary center in high yields with excellent regio-, diastereo-, and enantioselectivity. The application of chiral P,S ligands and the unique effect of α-aryl groups on the iminoesters are key to the success of this method. The practicality and versatility of the reaction are also demonstrated.