Exploring the Reactivity of N-Alkynylated Sulfoximines: Regioselective Hydroacyloxylations and Hydroaminations

Silver-mediated Room Temperature Reactions for the Synthesis of N-α-Ketoacyl Sulfoximines and N-α,β-Unsaturated Acyl Sulfoximines

Here, we report a silver-mediated coupling of acetylenes with sulfoximines to synthesize N-α-ketoacyl sulfoximines and N-α,β-unsaturated acyl sulfoximines. The reactions are performed under an open atmosphere using the oxidant K₂S₂O₈ and the ligand 2,2-bipyridyl. However, the fate of the product formation is controlled by the type of substrate used. The coupling between aryl acetylenes and sulfoximines afforded the N-α-ketoacylsulfoximines, while the alkyl acetylenes provided the N-α,β-unsaturated acyl sulfoximines. Controlled experiments reveal the differential reactivity patterns of substrates. The labeling ¹⁸O experiments showed that water is the source of the incoming oxygen atom for the keto group of N-α-ketoacyl sulfoximines and N-α,β-unsaturated acyl sulfoximines.

Selectivity Controlled Hydroamination of Alkynes to Sulfonyl Fluoride Hubs: Development and Application

A hydroamination of unactivated alkynes and lithium bis(fluorosulfonyl)imide (LiN(SO₂F)₂) is described under mild conditions, affording a single regioisomer of the sulfonyl fluorides. This method features broad functional group compatibility and delivers the target vinyl fluorosulfonimides in good to excellent yields. Moreover, gram-scale hydroamination of terminal and internal alkynes is achieved. Further transformations exploiting the reactivity of the vinyl fluorosulfonimide are subsequently developed for the synthesis of fluorosulfates and diphenyl sulfate.

Visible-Light-Mediated α-Ketoacylations of NH-Sulfoximines with gem-Difluoroalkenes

A photochemical approach for the preparation of α-keto-N-acyl sulfoximines from NH sulfoximines and gem-difluoroalkenes has been developed. In the presence of NBS, the reactions proceed in air without the need of a photocatalyst or additional oxidant. Results of mechanistic studies suggest that the two oxygens in the products stem from water and dioxygen.

Pd/Norbornene Collaborative Catalysis on the Divergent Preparation of Heterocyclic Sulfoximine Frameworks

Pd/Norbornene cocatalyzed tandem C-H activation/annulation reactions of free NH-sulfoximines with aryl iodides to produce diverse polyheterocyclic sulfoximines in highly chemoselective models are reported. The reaction tolerated a broad range of functional groups under external oxidant-free conditions. The preliminary mechanistic studies using density functional theory (DFT) calculations highlighted the key role of a Pd^IV intermediate.

Synthesis of fully-substituted 1,2,3-triazoles via copper(i)-catalyzed three-component coupling of sulfoximines, alkynes and azides

A copper(i)-catalyzed three-component reaction of sulfoximines, alkynes and azides is described, affording a variety of 1,2,3-triazolyl-5-sulfoximines in moderate to good yields.

Stereoselective synthesis of 4-aminobenzo[c][1,2]thiazine via modification of the Harmata benzothiazine synthesis

A stereoselective synthesis of 4-aminobenzothiazines was developed through a modified Harmata benzothiazine synthesis.

Functionalized α,β-ynones: efficient ligand for Cu catalyzed Sonogashira-type cross-coupling reaction

1,3-Yones as σ-, π-electron donating ligands significantly accelerated the cross-coupling reactions of aryl iodides with terminal alkynes, in which as low as 0.1 to 1 mol% of CuI were efficiently activated.