Metal-Free Transformation of Sulfonyl Oxime Ethers with Amines to Oxime Ethers.

Sulfonyl oxime ethers undergo facile radical substitutions with various amines to yield the corresponding oxime ethers. An efficient arylation of sulfonyl oxime ethers was accomplished under ambient temperature and metal-free conditions, with a wide range of functional group tolerance. Mechanistic investigations indicate that a phenyl radical is involved in the catalytic cycle.

Photocatalytic site-selective C-H difluoroalkylation of aromatic aldehydes.

The direct photocatalyzed para-selective CAr-H difluoroalkylation of aromatic aldehyde derivatives has been accomplished using a newly explored catalytic system. In addition, when using para-substituted benzaldehydes as substrates, ortho-selective CAr-H difluoroalkylation was also accomplished. It is worth noting that all the above site-selectivity is opposite to traditional Friedel-Crafts reactions of aromatic aldehydes. The preliminary mechanistic investigations indicate that an electrophilic difluoroalkyl radical is involved in the catalytic cycle.

Irradiation-Induced Cobaloxime-Catalyzed C-H Monofluoroalkylation of Styrenes at Room Temperature.

A cobaloxime-catalyzed photochemical synthesis of allyl monofluorides from styrenes is described herein. This method is characterized by mild reaction conditions, low-cost catalyst, and broad substrate scope. Furthermore, this convenient method will provide a facile synthesis toward novel monofluoroalkylated natural product and pharmaceutical derivatives. Mechanistic investigations indicate that a monofluoroalkyl radical is involved in the catalytic cycle.

Cu(II)-Mediated Decarboxylative Trifluoromethylthiolation of α,ß-Unsaturated Carboxylic Acids.

A tunable method for the direct trifluoromethylthiolation of α,ß-unsaturated carboxylic acids was developed to afford trifluoromethylthiolated ketones or alkenes. The reaction proceeds smoothly under mild conditions and shows an excellent functional group tolerance.

Visible-Light-Enabled Decarboxylative Mono- and Difluoromethylation of Cinnamic Acids under Metal-Free Conditions.

Several new mono- and difluoromethylation reactions of cinnamic acids using an Eosin Y catalytic system are reported. An efficient alkene fluoromethylation of α,ß-unsaturated carboxylic acids was accomplished under ambient temperature and metal-free conditions, with a wide range of functional group tolerance. A mechanism that involves a radical process is proposed for this reaction.