Cobalt- or rhodium-catalyzed synthesis of 1,2-dihydrophosphete oxides via C-H activation and formal phosphoryl migration

A highly stereo- and chemoselective intermolecular coupling of diverse heterocycles with dialkynylphosphine oxides has been realized via cobalt/rhodium-catalyzed C-H bond activation. This protocol provides an efficient synthetic entry to functionalized 1,2-dihydrophosphete oxides in excellent yields via the merger of C-H bond activation and formal 1,2-migration of the phosphoryl group. Compared with traditional methods of synthesis of 1,2-dihydrophosphetes that predominantly relied on stoichiometric metal reagents, this catalytic system features high efficiency, a relatively short reaction time, atom-economy, and operational simplicity. Photophysical properties of selected 1,2-dihydrophosphete oxides are also disclosed.

A visible-light-induced bromine radical initiates direct C-H alkylation of heteroaromatics

Herein, a photoinduced direct C(sp2)-H alkylation of N-heteroaromatics by using commercially available tetrabutylammonium tribromide (TBATB) as a HAT reagent is described. The method uses O2 as the oxidant, and features metal-free, mild reaction conditions and good functional group compatibility.

Organoboron/iodide-catalyzed photoredox N-functionalization of NH-sulfoximines/sulfonimidamides

An aminoquinolate diarylboron (AQDAB) and tetrabutylammonium iodide (TBAI) co-catalyzed photoredox process for N-functionalization of NH-sulfoximines/sulfonimidamides has been successfully developed. This protocol can afford the corresponding N-sulfenylated and N-phosphonylated products in good to excellent yields under conditions without metallic (photo)catalysts, external oxidants, or acidic/basic additives. A wide range of functional groups are tolerated, and the N-phosphonylated products of NH-sulfonimidamides have been reported for the first time.

Visible light-induced metal-free chemoselective oxidative cleavage of benzyl C-heteroatom (N, S, Se) bonds utilizing organoboron photocatalysts

The oxidation process is widely explored and used to synthesize diverse organic chemicals. Herein, a unified metal-free photooxidative platform for the cleavage of C-heteroatom bonds has been developed. In these reactions, the aminoquinolate diarylboron (AQDAB) complex is utilized as the photocatalyst, instigating the oxidation process induced by visible light. The cleavage of C-heteroatom bonds can be achieved chemoselectively, affording the formal carbonylation product of C-N, C-S, and C-Se bonds. This method provides a channel for connecting amines, thiols, or selenides with the carbonyl compounds directly, broadening the potential applications of oxidation as a synthetic tool.

Ni-Catalyzed Asymmetric C-P Cross-Coupling Reaction for the Synthesis of Chiral Heterocyclic Phosphine Oxides

Nickel performs excellently in C-C and C-X cross-coupling reactions. Here, we disclose a Ni(II)-catalyzed asymmetric C-P cross-coupling reaction to afford valuable chiral heterocyclic tertiary phosphine oxides. The method is mild and efficient, which invokes a self-sustained nickel catalytic cycle without an external reductant, light irradiation, or electricity.

Visible Light-Mediated Organoboron-Catalyzed Metal-Free Synthesis of Silanols from Silanes

Herein, a four-coordinated organoboron compound, aminoquinoline diarylboron (AQDAB), is utilized as the photocatalyst in the oxidation of silane to silanol. This strategy effectively oxidizes Si-H bonds, affording Si-O bonds. Generally, the corresponding silanols can be obtained in moderate to good yields at room temperature under oxygen atmospheres, representing a green protocol to complement the existing preparation methods for silanols.

Three-Component Oxychalcogenation of Alkenes under Metal-Free Conditions: A Tetrabutylammonium Tribromide-Catalyzed System

A three-component oxychalcogenation reaction, from alkenes, diselenides/thiophenols, and H₂O/alcohols, has been realized herein. Tetrabutylammonium tribromide (TBATB) and dimethylsulfoxide (DMSO) are utilized as the catalyst and the terminal oxidant, respectively, to enable this difunctionalization transformation. The metal-free reaction system shows good functional group compatibility, providing a unified and practical approach to access β-hydroxyl or β-alkoxy organochalcogenides.

Synthesis of β-Arylseleno Sulfoximines: A Metal-Free Three-Component Reaction Mediated by Tetrabutylammonium Tribromide

A tetrabutylammonium tribromide-mediated three-component reaction of alkenes, diselenides, and sulfoximines has been established herein, providing direct and metal-free access to diverse β-arylseleno sulfoximine derivatives. This regioselective sulfoximido-selenization protocol proceeds efficiently under mild and ambient conditions with generally good yields. This strategy is featured by step and atom economy, practicability, a broad substrate scope, and gram-scale synthesis.