A Formal 1,2-Stevens Rearrangement of Thioester Ylides as a Single-Atom Molecular Editing Tool

A rhodium-catalyzed reaction of thioesters with diazo reagents was recognized as a powerful and unprecedented tool for single-atom molecular editing by the insertion of a single carbon atom into the C(O)─S thioester bond, thereby leading to various α-thioketones possessing a quaternary carbon atom. A selective and precise defunctionalization of the polyfunctionalized products further demonstrated the synthetic utility of the reaction for the synthesis of more common structural classes of compounds.

Modular Synthesis of Tetrasubstituted Vinyl Sulfides via One-Pot Sequential Carbene Transfer Reaction from Thiols with α-Diazo Carbonyl Compounds

We present a one-pot reaction that offers an efficient approach to synthesizing tetrasubstituted vinyl sulfides with high stereoselectivity. This method involves the sequential Wolff rearrangement, ylide formation, and [1,4]-aryl transfer by utilizing aryl and alkyl thiols and α-diazo carbonyl compounds as substrates. Notably, this reaction features commercially available materials, straightforward operation, atom economy, and broad substrate scope. Moreover, the primary photophysical properties (aggregation-induced emission effect) of the products were also investigated, which might be useful in functional materials via structural modification.

PPh3-Mediated Cascade Reaction of 2-Alkynylnitrobenzenes and Thioureas for the Construction of Imidazo[4,5-b]indole-2-thiones

A simple method for the preparation of imidazo[4,5-b]indole-2-thiones from 2-alkynylnitrobenzenes and thioureas is described. In the reaction, a Wittig-like process was triggered by PPh₃ and followed by a cyclization step. The products were afforded in yields of 70-98% under mild conditions. Additionally, the 2-alkynylnitrobenzenes were stable and could be prepared via a simple coupling step.

Rhodium-Catalyzed 1,4-Aryl Rearrangement of Sulfur Ylide for the Synthesis of 2-Pyridyl Thioethers

We report a novel rhodium-catalyzed rearrangement involving N-substituted 2-thiopyridones and diazoesters. This reaction proceeds through the rhodium-catalyzed formation of sulfur ylides, followed by a direct C-N bond cleavage to achieve N-to-C 1,4-pyridyl migration. The protocol can be used to construct various thiopyridines possessing tetrasubstituted carbon stereocenters in moderate to excellent yields, which expands the transformation pattern of sulfur ylide intermediates in rearrangement reactions.

A rhodium-catalyzed ylide formation/Smiles rearrangement reaction of chalcogenide ether and triazoles

A Rh(ii)-catalyzed highly stereoselective chalcogenide ylide formation/Smiles rearrangement reaction of diaryl thioether/selenoethers and triazoles was successfully developed.

One-Pot Modified Madelung Synthesis of 3-Tosyl- and 3-Cyano-1,2-disubstituted Indoles

A One-pot, two-step procedure for the synthesis of 1,2-disubstituted-3-tosyl and 1,2-disubstituted-3-cyanoindoles from the corresponding N-(o-tolyl)benzamides is reported. The developed procedure is operationally simple, does not utilize any transition metals, and provides variably substituted indoles in good yields from readily available starting materials.

Rhodium-catalyzed denitrogenative gem-difunctionalization of pyridotriazoles with thioesters: formal carbene insertion into C(O)-S bonds

A formal carbene insertion into C(O)-S bonds to access α-quaternary pyridines was achieved via a rhodium(II)-catalyzed in situ formation of sulfonium ylides from pyridotriazoles with thioesters followed by acyl group migration. This protocol has enabled an efficient denitrogenative gem-acylthiolation of pyridotriazoles to incorporate an acyl, pyridyl, and sulfur-substituted quaternary carbon center with high selectivity, broad substrate scope, and good functional group tolerance.

Modular and stereoselective synthesis of tetrasubstituted vinyl sulfides leading to a library of AIEgens

Tetraarylethylenes exhibit intriguing photophysical properties and sulfur atom frequently play a vital role in organic photoelectric materials and biologically active compounds. Tetrasubstituted vinyl sulfides, which include both sulfur atom and tetrasubstituted alkenes motifs, might be a suitable skeleton for the discovery of the new material molecules and drug with unique functions and properties. However, how to modular synthesis these kinds of compounds is still challenging. Herein, a chemo- and stereo-selective Rh(II)-catalyzed [1,4]-acyl rearrangements of α-diazo carbonyl compounds and thioesters has been developed, providing a modular strategy to a library of 63 tetrasubstituted vinyl sulfides. In this transformation, the yield is up to 95% and the turnover number is up to 3650. The mechanism of this reaction is investigated by combining experiments and density functional theory calculation. Moreover, the "aggregation-induced emission" effect of tetrasubstituted vinyl sulfides were also investigated, which might useful in functional material, biological imaging and chemicalnsing via structural modification.

Catalytic Insertion Reactions of α-Imino Carbenoids

Over the past decade, α-imino carbenoids generated via transition metal (such as rhodium, nickel, copper, palladium, silver) catalyzed denitrogenative ring-opening of N-sulfonyl-1,2,3-triazoles have found an extensive account of applications in synthetic organic chemistry. Particularly, they have been widely utilized as a donor/acceptor carbene complex in a range of transformations leading to diverse nitrogen containing compounds and heterocycles. Along the same direction, 3-diazoindolin-2-imines were successfully applied as an alternative source of α-imino carbenoid precursors for the development of a number of methodologies to access diverse indole derivatives. This review summarizes the insertion reactions of α-imino metal carbenes derived from N-sulfonyl-1,2,3-triazoles and 3-diazoindolin-2-imines.

Recent advances in the synthesis of indole embedded heterocycles with 3-diazoindolin-2-imines

The preparations, reactivity and synthetic applications of 3-diazoindolin-2-imines, a valuable class of α-diazo amidines, are reviewed.

Cu-Catalyzed o-Amino Benzofuranthioether Formation from N-Tosylhydrazone-Bearing Thiocarbamates and Arylative Electrophiles

An important framework of o-amino benzofuranthioethers was constructed by Cu-catalyzed arylative cyclization of N-tosylhydrazone-bearing thiocarbamates with silylaryl triflates or ArI. This transformation provides a novel strategy for the synthesis of valuable arylative o-amino benzofuranthioethers in moderate yields which could not be obtained from known methods. The reaction features smart design, efficient construction, and mild reaction conditions.