Base-Promoted Annulated Aromatization of Aryl Acetylenes with Dimethyl Sulfoxide to Access Symmetrical/Unsymmetric m-Terphenyl

A protocol for selective and efficient synthesis of symmetrical and unsymmetrical m-terphenyls is presented among aryl acetylene and DMSO in the presence of KOH and methanol. In this reaction, two molecules of aryl acetylene contribute four carbons, and DMSO, as a dual carbon donor, provides two carbons to a new aromatic ring. This protocol can be tolerated for the electron-donating or disubstituted phenylacetylenes as well as the heterocyclic acetylene derivatives.

Vinylation of N-Heteroarenes through Addition/Elimination Reactions of Vinyl Selenones

A new protocol for the synthesis of N-vinyl azoles using vinyl selenones and azoles in the presence of potassium hydroxide was developed. This reaction proceeded under mild and transition metal-free conditions through an addition/elimination cascade process. Both aromatic and aliphatic vinyl selenones and various mono-, bi- and tri-cyclic azoles can be tolerated and give terminal N-vinyl azoles in moderate to high yields. A plausible mechanism is also proposed.

Lewis Acid-Promoted Typical Friedel-Crafts Reactions Using DMSO as a Carbon Source

This study reports a mild and efficient synthetic protocol for the synthesis of symmetrical and unsymmetrical diarylmethanes (DAMs). Using DMSO as the C₁ source and TMSOTf as the Lewis acid promoter, a series of functionalized symmetrical and unsymmetrical DAMs were synthesized in high yields. Gratifyingly, DMSO plays a dual role as a solvent and a C₁ source and can also be replaced with its deuterated counterpart, DMSO-d₆, enabling the incorporation of the -CD₂ moiety into the diarylmethane skeleton. The developed approach has been applied to a wide range of substrates having various functional groups, and this protocol has also been extended to the synthesis of an anti-breast cancer agent and an anticoagulant agent using common feedstock compounds. In addition, the postulated mechanism has been explicitly demonstrated via control experiments.

Regioselective Synthetic Approach to Higher Alkenes from Lower Alkenes with Sulfoxides in the Fe3+/H2O2 System via Direct Alkylation or Arylation of the Csp2-H Bond on the C═C Bond of Alkenes

The regioselective synthetic approach to higher alkenes from lower alkenes by using sulfoxides as alkyl or aryl reagents in the Fe³⁺/H₂O₂ system has been developed. This reaction realized direct alkylation or arylation of alkenes. In this reaction, sulfoxides afforded one Csp³ or Csp² atom to the C═C bond of alkenes; one new Csp²-Csp³ bond or Csp²-Csp² bond was formed. Nearly 40 products including di-, tri-, and tetra-substituted products were regioselectively synthesized. Both aliphatic and aromatic alkenes could participate in this reaction. Moreover, not only dimethyl sulfoxide but also three other sulfoxides can be applied to this reaction, including diethyl, dibenzyl, and diphenyl sulfoxide. The mechanism studies showed that this reaction may experience a coupling process via radical addition-elimination and the Fe³⁺/H₂O₂ system made the sulfoxides offered one alkyl or aryl radical to the C═C bond of alkenes.

Selective synthesis of alkyl amines and N-vinylazoles from vinyl sulfonium salts with N-nucleophiles

Herein, we developed an efficient and green method for the synthesis of various alkyl amines via C(sp3)−S bond cleavage of vinylsulfonium salts. The reaction proceeds under an air atmosphere with...

DMSO as a C1 Source for [2 + 2 + 1] Pyrazole Ring Construction via Metal-Free Annulation with Enaminones and Hydrazines

A cascade reaction between enaminones, hydrazines, and dimethyl sulfoxide (DMSO) for the synthesis of 1,4-disubstituted pyrazoles catalyzed by molecular iodine in the presence of Selectfluor has been realized. DMSO plays a dual role as the C₁ source and the reaction medium. In addition, the synthesis of 1,3,4-trisubstituted pyrazoles using aldehydes as alternative C₁ building blocks has also been achieved.