A Copper(I)-Catalyzed Sulfonylative Hiyama Cross-Coupling

Experimental and computational insights into the mechanism of the copper(i)-catalysed sulfonylative Suzuki-Miyaura reaction

A mechanistic study into the copper(i)-catalysed sulfonylative Suzuki-Miyaura reaction, incorporating sulfur dioxide, is described. Utilising spectroscopic and computational techniques, an exploration into the individual components of the competing catalytic cycles is delineated, including identification of the resting state catalyst, transmetalation of arylboronic acid onto copper(i), the sulfur dioxide insertion process, and the oxidative addition of aryl halide to Cu^I. Studies also investigated prominent side-reactions which were uncovered, including a competing copper(ii)-catalysed mechanism. This led to an additional proposed and connected Cu^I/Cu^II/Cu^III catalytic cycle to account for by-product formation.

A fruitful century for the scalable synthesis and reactions of biphenyl derivatives: applications and biological aspects

This review provides recent developments in the current status and latest synthetic methodologies of biphenyl derivatives. Furthermore, this review investigates detailed discussions of several metalated chemical reactions related to biphenyl scaffolds such as Wurtz-Fittig, Ullmann, Bennett-Turner, Negishi, Kumada, Stille, Suzuki-Miyaura, Friedel-Crafts, cyanation, amination, and various electrophilic substitution reactions supported by their mechanistic pathways. Furthermore, the preconditions required for the existence of axial chirality in biaryl compounds are discussed. Furthermore, atropisomerism as a type of axial chirality in biphenyl molecules is discussed. Additionally, this review covers a wide range of biological and medicinal applications of the synthesized compounds involving patented approaches in the last decade corresponding to investigating the crucial role of the biphenyl structures in APIs.

Understanding the Organometallic Step: SO2 Insertion into Bi(III)-C(Ph) Bond

Heavier main-group element-catalyzed reactions provide an increasingly attractive tool to perform transformations mimicking the behaviors of transition metal catalysts. Recently, Magre and Cornella reported a Bi-catalyzed synthesis of aryl sulfonyl fluorides, which involves a fundamental organometallic step of SO₂ insertion into the Bi-Ph bond. Our theoretical studies reveal that i) the ability of hypervalent coordination of the Bi(III) center allows facile coordination sphere expansion for the SO₂ coordination via one oxygen atom; and ii) the high polarity of the Bi-Ph bond makes the Ph migration from the Bi(III) center feasible. These features enable the heavier main group element to resemble the transition metal having flexibility for ligand association and dissociation. Furthermore, iii) the available π electron pair of the migrating Ph group stabilizes the SO₂ insertion transition state by maintaining interaction with the Bi(III) center during migration. The insight helps us better understand the heavier main-group catalysis.

Aryldiazonium Salts and DABSO: a Versatile Combination for Three-Component Sulfonylative Cross-Coupling Reactions

A combination of aryldiazonium salts and DABSO provides a unique opportunity for sulfonylative multicomponent cross-coupling reactions. Here, a copper-catalyzed three-component cross-coupling of aryldiazonium salts, DABSO with arylboronic acids to obtain medicinally relevant unsymmetrical diarylsulfones is disclosed. Interestingly, a catalyst-free approach for the synthesis of arylvinylsulfones from the corresponding vinyl boronic acid or vinyl halides is explored under basic condition. Tethered aryldiazonium salts provided the corresponding annulated alkylvinylsulfones via alkene difunctionalization under the same transition metal-free condition. Mechanistically, these multicomponent reactions proceed through a single electron pathway by the formation of arylsulfonyl radical as a key intermediate.

DABSO – A Reagent to Revolutionize Organosulfur Chemistry

The introduction of easy-to-handle SO2 surrogates has transformed the field of sulfur chemistry, enabling methodologies utilizing SO2 to be carried out without specialized apparatus, and paving the way for the development of new procedures. This review highlights some of the varied and significant developments associated with one of the most prominent SO2 surrogates: DABSO.

1 Introduction

2 DABSO

3 Reactions with Nucleophilic Reagents

4 Metal-Catalyzed Reactions

4.1 Palladium-Catalyzed Reactions

4.2 Other Transition-Metal Catalysis

5 Radical Reactions

5.1 Aryldiazonium Salts

5.2 Other Aryl Radical Precursors

5.3 Alkyl Radical Precursors

6 Conclusion

Applications of DABSO as an SO2 Gas Surrogate in Organic Synthesis

1,4-Diazabicyclo[2.2.2]octane bis(sulfur dioxide), DABCO.SO2, or DABSO, a bench-stable colorless solid, is industrially produced by the reaction of DABCO with the condensed and bubbled sulfur dioxide gas at low temperatures. However,...