Synthesis of 2,3-Dihydrobenzofurans via a Photochemical Gold-Mediated Atom Transfer Radical Addition Reaction

A light-mediated cyclization reaction initiated by an atom transfer radical addition (ATRA) of haloalkanes onto alkenes was exploited for the synthesis of functionalized dihydrobenzofurans. Initial investigation indicated that the dimeric gold catalyst [Au2(μ-dppm)2Cl2] can effectively be used for intermolecular ATRA reactions. Further, the reactivity was applied in a cascade-like cyclization for the preparation of dihydrobenzofuran derivatives. With the presented photochemical approach, the functionalization can be achieved directly from ortho-allylphenols in yields of up to 96% under mild conditions.

Palladium-catalyzed cascade 5-exo-trig radical cyclization/aromatic C-H alkylation with unactivated alkyl iodides

A novel and convenient palladium-catalyzed cascade 5-exo-trig radical cyclization/aromatic C-H alkylation with unactivated alkyl iodides has been described. This strategy provides an efficient access to a variety of 3a-methyl-1,2,3,3a,4,8b-hexahydroindeno[1,2-b]pyrrole derivatives, which facilitate access to a series of medically important heterocyclic bioactive molecules. This protocol involves mild catalytic reaction conditions and shows high functional group tolerance with high stereoselectivity. Mechanistic investigations reveal that an alkyl radical pathway is involved in this reaction.

Intramolecular Pd-Catalyzed Formal anti-Carboalkoxylation of Alkynes: Access to Tetrasubstituted Enol Ethers

An intramolecular Pd-catalyzed formal anti-carboalkoxylation reaction is presented that provides access to tetrasubstituted enol ethers. The key to success is a cascade consisting of a formal anti-carbopalladation of a carbon-carbon triple bond followed by a nucleophilic attack of a hydroxy group at the emerging vinyl organopalladium species. The desired transformation proceeded smoothly with primary, secondary, and tertiary alcohols, and even with phenols. Depending on the substitution pattern of the enol ethers, a further Tsuji-Trost-type step may occur resulting in oligocyclic ketals.

Palladium-Catalyzed Atom-Transfer Radical Cyclization at Remote Unactivated C(sp3 )-H Sites: Hydrogen-Atom Transfer of Hybrid Vinyl Palladium Radical Intermediates

A novel mild, visible-light-induced palladium-catalyzed hydrogen atom translocation/atom-transfer radical cyclization (HAT/ATRC) cascade has been developed. This protocol involves a 1,5-HAT process of previously unknown hybrid vinyl palladium radical intermediates, thus leading to iodomethyl carbo- and heterocyclic structures.

Sulfonic acid-functionalized magnetic nanoparticles as a recyclable and eco-friendly catalyst for atom economical Michael addition reactions and bis indolyl methane synthesis

Sulfonic acid-functionalized magnetic nanoparticles as a recyclable and eco-friendly catalyst for atom economical Michael addition reaction and bis indolyl methane synthesis.