A Dual Cobalt and Photoredox Catalysis for Hydrohalogenation of Alkenes.

We demonstrate hydrohalogenation of aliphatic alkenes with collidine·HX salts through dual photoredox/cobalt catalysis. The dual catalysis enables conversion of a proton and a halide anion from collidine·HX salt to a nucleophilic hydrogen radical equivalent and an electrophilic halogen radical equivalent and delivery of them to an alkene moiety. This protocol allows for introduction of fluorine, chlorine, bromine, or iodine atom to alkene, producing highly functionalized alkyl halides.

Decarboxylative N-Alkylation of Azoles through Visible-Light-Mediated Organophotoredox Catalysis.

An organophotoredox-catalyzed decarboxylative cross-coupling between azole nucleophiles and aliphatic carboxylic acid-derived redox-active esters is demonstrated. This protocol efficiently installs various tertiary or secondary alkyl fragments onto the nitrogen atom of azole nucleophiles under mild and transition-metal-free conditions. The pyridinium additive successfully inhibits the formation of elimination byproducts from the carbocation intermediate.

Organophotoredox-Catalyzed Three-Component Coupling of Heteroatom Nucleophiles, Alkenes, and Aliphatic Redox Active Esters.

This manuscript describes a visible-light-mediated organophotoredox catalytic process for vicinal difunctionalization of alkenes using heteroatom nucleophiles and aliphatic redox active esters. A wide range of heteroatom nucleophiles including alcohols, water, carboxylic acids, amides, and halogens can be used for this reaction. This radical relay type reaction allows forging of C(sp)-C(sp) with a carbon-centered radical and C(sp)-heteroatom bonds with a benzyl cation on the vinylarenes with complete regioselectivity in a single step.

Organophotoredox-Catalyzed Decarboxylative C(sp)-O Bond Formation.

This manuscript reports a visible-light-mediated organosulfide catalysis that enables the decarboxylative coupling between simple aliphatic alcohol and tertiary or secondary alkyl carboxylic acid-derived redox active esters to produce a C(sp)-O-C(sp) fragment. Results of the coupling using other heteroatom nucleophiles such as water, amides, and thiols are also described.