Efficient synthesis of SCF3-containing 3-alkenylquinoxalinones via three-component radical cascade reaction

An efficient and practical method for the synthesis of 3-alkenylquinoxalinones containing the SCF3 group has been readily developed through a three-component radical cascade reaction involving quinoxalinones, alkynes and AgSCF3. The reaction was found to be compatible with a variety of substrates and exhibited a high functional group tolerance and complete E-selectivity. The preliminary study suggests the involvement of a SCF3 radical in the transformation.

Photoredox-Catalyzed 1,4-Peroxidation-Sulfonylation of Enynones: A Three-Component Radical Coupling Approach for the Synthesis of Highly Functionalized Allenes

An Eosin Y-catalyzed visible light-promoted 1,4-peroxidation-sulfonylation of enynones was achieved to give tetrasubstituted allenes. The photoredox catalysis of Eosin Y allowed the concomitant formation of peroxy and sulfonyl radicals, where the preferential peroxy radical addition to the alkene moiety of enynones resulted in the subsequent α-keto radical-sulfonyl radical cross couplings. The developed photoredox catalysis of Eosin Y demonstrates a regioselective 1,4-diradical addition strategy, opening up a new possibility of diradical functionalization of conjugate systems.

Dealkenylative Functionalizations: Conversion of Alkene C(sp3)-C(sp2) Bonds into C(sp3)-X Bonds via Redox-Based Radical Processes

This review highlights the history and recent advances in dealkenylative functionalization. Through this deconstructive strategy, radical functionalizations occur under mild, robust conditions. The reactions described proceed with high efficiency, good stereoselectivity, tolerate many functional groups, and are completed within a matter of minutes. By cleaving the C(sp3)-C(sp2) bond of terpenes and terpenoid-derived precursors, rapid diversification of natural products is possible.

TBAI-Catalyzed Regioselective Hydroxyperoxidation of 1-Aryl/Alkyl-1,3-dienes

An efficient, mild, and economical approach for regioselective synthesis of 4-aryl/alkyl-1-peroxy-but-3-en-2-ols from 1-substituted-1,3-butadienes using hydroperoxides and catalyzed by TBAI has been developed. This method can be executed in a simple operation with no dry conditions required and having tolerance to a wide range of substrates to access corresponding hydroxyperoxidates in good yields. Thus, an excellent regioselective orthogonal dioxygenation in a diene system has been achieved.

Cascade Oxidative Trifluoromethylthiolation and Cyclization of 3-Alkyl-1-(2-(alkynyl)phenyl)indoles

Persulfate-promoted radical cascade trifluoromethylthiolation and cyclization of 3-alkyl-1-(2-(alkynyl)phenyl)indoles with AgSCF₃ were investigated. This protocol provides a novel route to CF₃S-substituted indolo[1,2-a]quinoline-7-carbaldehydes and CF₃S-substituted indolo[1,2-a]quinoline-7-methanone derivatives via the formation of the C-SCF₃ bond and C-C bond and benzylic carbon oxidation in a single step. This reaction can accommodate a broad range of functional groups. The single-crystal X-ray diffraction data confirm the chemical structure of the product. A scale-up experiment and radical inhibition experiments were operated in the reaction system. Photophysical properties of some selected 5-((trifluoromethyl)thio)indolo[1,2-a]quinoline-7-carbaldehydes were studied by UV-visible and fluorescence spectroscopy.

When all C-C breaks LO-Ose

Organic peroxides are becoming popular intermediates for novel chemical transformations. The weak O-O bond is readily reduced by transition metals, including iron and copper, to initiate a radical cascade process that breaks C-C bonds. Great potential exists for the rapid generation of complexity, originating from the ability to couple the resulting free radicals with a wide range of partners. First, this review article discusses the history and synthesis of organic peroxides, providing the context necessary to understand this methodology. Then, it highlights 91 examples of recent applications of the radical functionalization of C-C bonds accessed through the transition metal-mediated reduction of organic peroxides. Finally, we provide some comments about safety when working with organic peroxides.

Nickel-Catalyzed Three-Component Tandem Radical Cyclization 1,5-Difunctionalization of 1,3-Enynes and Alkyl Bromide

A nickel-catalyzed three-component tandem radical cyclization reaction of aryl bromides with 1,3-enynes and aryl boric acids to construct γ-lactam-substituted allene derivatives has been described. This protocol provides lactam alkyl radicals through the free radical cyclization process, which can be effectively used to participate in the subsequent multicomponent coupling reaction so that 1,3-enynes could directly convert into corresponding poly-substituted allene compounds. In addition, this efficient method enjoys a broad substrate scope and provides a series of 1,5-difunctionalized allenes in a one-pot reaction.

Copper(I)-Catalyzed Three-Component Selenosulfonation of Maleimides with Sulfonyl Hydrazides and Diselenides via Radical Relay

By employing Cu(CH₃CN)₄PF₆ as the catalyst and tert-butyl hydroperoxide as the oxidant, we realized a three-component radical selenosulfonation of substituted maleimides, sulfonyl hydrazides, and diphenyl diselenides, providing a series of 3,4-selenosulfonylated succinimides in moderate to good yields. This reaction features broad substrate scopes, high functional-group tolerability, and feasibility of gram-scale synthesis, enabling one-step construction of C-SO₂ and C-Se bonds under mild reaction conditions. Preliminary mechanistic studies support the free-radical-induced pathway.

Regioselective Approach to β-Peroxyl Alcohols and Ethers from Alkenes

A different regioselective three-component reaction of alkenes, oxygen sources, and hydroperoxides mediated by ammonium iodine to α-oxyperoxidates has been developed. Mechanistic studies demonstrated that regioselective radical addition and subsequent S_N2 nucleophilic substitution were possible for the formation of products. In addition to the traditional pathway of S_N2 reaction, that is, where nucleophiles attack the α-C atoms at the back side, an additional unusual transition configuration with the H₂O molecule attacking the α-C atom at the front side was obtained.

Silver-Mediated Radical Oxytrifluoromethylation of Unstaurated Carboxylic Acids for the Synthesis of γ-Trifluoromethylthio Lactones

An efficient silver-mediated oxidative trifluoromethylthiolation of unsaturated carboxylic acids to constructed trifluoromethylthiole-containing lactones has been disclosed. This protocol without added other metal-catalyst, preliminary mechanism investigations suggested that a free-radical pathway...

Concomitant Functionalization of Two Different Ketones by Merging Brønsted Acid Catalysis and Radical Relay Coupling

In previous literature, incorporation of functional groups at the α-position of unactivated carbonyl compounds was mainly restricted to one kind of corresponding precursors. Herein, we report the concomitant functionalization of...

A Mn-catalyzed remote C(sp3)-H bond peroxidation triggered by radical trifluoromethylation of unactivated alkenes

A manganese-catalyzed radical relay strategy for the remote trifluoromethylation-peroxidation of unactivated alkenes is disclosed. The electrophilic CF3 group was added to the C[double bond, length as m-dash]C double bonds to afford remote C-centered radicals upon 1,5-HAT, which could be efficiently trapped by Mnn+1OOBu-t species to deliver 1,6-difunctionalized products selectively under mild conditions. t-BuOOH serves as both the oxidant and the peroxy precursor in this transformation.

Directed Cobalt-Catalyzed C-H Activation to Form C-C and C-O Bonds in One Pot via Three-Component Coupling

Herein, we disclose an efficient cobalt-catalyzed three-component coupling of benzamides, diazo compounds, and tert-butyl hydroperoxide, which provides an efficient approach to construct C(sp²)-C(sp³) and C-O bonds in one-pot accompanied with C-H activation. This protocol features low catalyst loading (4 mol %), the avoidance of additives, and excellent functional group compatibility, providing three-component coupling adducts with high yields under mild conditions (up to 88%). Mechanism studies show that the reaction may involve a radical process.

Recent advances in intermolecular 1,2-difunctionalization of alkenes involving trifluoromethylthiolation

Trifluoromethylthiolative difunctionalization of alkenes, a cheap and abundant feedstock, which installs a trifluoromethylthiol (SCF₃) group and another unique functional group across the carbon–carbon double bonds, provides an ideal strategy for the preparation of β-functionalized alkyl trifluoromethyl sulfides and has become a hot topic recently.