Acid-Mediated Intramolecular Cyclizations of (N-Aryl)-acetylenic Sulfonamides: Synthesis of Fused and Spirocyclic Sultams

Herein, we report acid-mediated divergent annulations of (N-aryl)-alkynyl sulfonamides. The substituent at the para position of the N-aryl group determines two diverse reaction paths, leading to the selective assembly of benzo-fused sultams and spirocyclic sultams. This strategy provides a series of benzo/spiro-sultams with wide functional group compatibility and good to excellent yields under mild reaction conditions. Additionally, scale-up reaction and further transformations of the products were also carried out to demonstrate the utility of the protocol.

Reassembly and functionalization of N-CF3 pyridinium salts: synthesis of nicotinaldehydes

An unprecedented hydrolyzation-triggered ring opening and recyclization cascade to construct biologically interesting nicotinaldehydes.

Recent Advances in Catalytic Synthesis of Benzosultams

Benzosultams represent one category of multi-heteroatom heterocyclic scaffolds, which have been frequently found in pharmaceuticals, agricultural agents, and chiral catalysts. Given the diversely significant functions of these compounds in organic and medicinal chemistry, great efforts have been made to develop novel catalytic systems for the efficient construction of benzosultam motifs over the past decades. Herein, in this review, we mainly summarize the recent advances in the field of catalytic synthesis of benzosultams from 2017 to August of 2020, with an emphasis on the scopes and mechanisms of representative reactions.

Benzoazepine-Fused Isoindolines via Intramolecular (3 + 2)-Cycloadditions of Azomethine Ylides with Dinitroarenes

Aminobenzaldehydes bearing a pendant 3,5-dinitrophenyl group react thermally with N-substituted α-amino acids to form unprecedented benzoazepine-fused isoindolines. The reaction proceeds via a dearomatization/rearomatization sequence involving an intramolecular (3 + 2)-cycloaddition between the in situ formed azomethine ylide and the dinitroarene. Various glycine derivatives are tolerated as well as branched substrates based on cyclic, α-mono-, and α,α-disubstituted amino acids, giving single diastereomers in many cases. The method is scalable and gives products with a nitro group ready for further manipulation.

Diastereoselective synthesis of novel tetra-and pentacyclic annulated coumarino-δ-sultam pyrrolidine, pyrrolizidine, pyrrolothiazole and isoxazolidine derivatives via intramolecular 1,3-dipolar cycloadditions

A facile and efficient strategy towards the novel tetra- and pentacyclic annulated coumarino-δ-sultam pyrrolidine, pyrrolizidine, pyrrolothiazole and isoxazolidine via intramolecular 1,3-dipolar cycloadditions of is described.