Copper-catalyzed cyclization reaction: synthesis of trifluoromethylated indolinyl ketones.

A novel, simple, effective and rapid synthetic method to construct the C-2 trifluoromethylated indolinyl ketones via a copper-catalyzed cyclization reaction between N-alkylaniline and ß-(trifluoromethyl)-α,ß-unsaturated enones was developed. The results of the control experiments show that the reaction may involve a radical mechanism by a single-electron transfer process. Moreover, a broad substrate scope and good functional groups, high diastereoselectivities (dr, up to >20 : 1) as well as gram-scale synthesis make this approach highly attractive.

Visible-light-induced oxidative formylation of N-alkyl-N-(prop-2-yn-1-yl)anilines with molecular oxygen in the absence of an external photosensitizer.

Visible-light-induced oxidative formylation of N-alkyl-N-(prop-2-yn-1-yl)anilines with molecular oxygen in the absence of an external photosensitizer was developed and afforded the corresponding formamides in good yields under mild conditions. The investigation of the mechanism disclosed that both the starting material and the product act as photosensitizers, and 1O2 and O2˙- are generated through energy transfer and a single electron transfer pathway and play an important role in the reaction.

Photocatalyst-free hypervalent iodine reagent catalyzed decarboxylative acylarylation of acrylamides with α-oxocarboxylic acids driven by visible-light irradiation.

A hypervalent iodine(iii) reagent catalyzed carbonylarylation of acrylamides with α-oxocarboxylic acids driven by visible-light without a photoredox catalyst has been developed. The reactions generate the corresponding products in good yields at room temperature. Experiments indicate that a blue LED (450-455 nm) is the most effective energy for the cleavage of the oxygen-iodine bond to initiate the reaction. Mechanistic studies further demonstrate that the reaction undergoes a cascade decarboxylative radical addition/cyclization process along with releasing CO2 and H2.

Sunlight-Driven Decarboxylative Alkynylation of α-Keto Acids with Bromoacetylenes by Hypervalent Iodine Reagent Catalysis: A Facile Approach to Ynones.

A novel and practical decarboxylative alkynylation of α-keto acids with bromoacetylenes is catalyzed by hypervalent iodine(III) reagents when irradiation by sunlight at room temperature. The product ynones are generated in good yields. Experiments show that results obtained with blue light (λ=450-455 nm) are comparable to those obtained when using sunlight. Mechanistic studies demonstrate that the sunlight-driven decarboxylation undergoes a radical process.