Silver-Catalyzed Intermolecular [3 + 2]/[5 + 2] Annulation of <i>N</i>‑Arylpropiolamides with Vinyl Acids: Facile Synthesis of Fused 2<i>H</i>‑Benzo[<i>b</i>]azepin-2-ones

A silver-catalyzed oxidative intermolecular [3 + 2]/[5 + 2] annulation of <i>N</i>-arylpropiolamides with 4-vinyl acids for producing fused 2<i>H</i>-benzo­[<i>b</i>]­azepin-2-ones is described. This radical-mediated annulation reaction features broad substrate scope and excellent selectivity, and enables the formation of three new C–C bonds through oxidative decarboxylation, [3 + 2]/[5 + 2] annulations, and C­(sp²)-H functionalization cascades. Employing this silver-catalyzed oxidative strategy, common terminal alkynes were successfully converted into cyclopentenes via intermolecular [3 + 2] annulation

Silver-Catalyzed Intermolecular [3 + 2]/[5 + 2] Annulation of <i>N</i>‑Arylpropiolamides with Vinyl Acids: Facile Synthesis of Fused 2<i>H</i>‑Benzo[<i>b</i>]azepin-2-ones

A silver-catalyzed oxidative intermolecular [3 + 2]/[5 + 2] annulation of <i>N</i>-arylpropiolamides with 4-vinyl acids for producing fused 2<i>H</i>-benzo­[<i>b</i>]­azepin-2-ones is described. This radical-mediated annulation reaction features broad substrate scope and excellent selectivity, and enables the formation of three new C–C bonds through oxidative decarboxylation, [3 + 2]/[5 + 2] annulations, and C­(sp²)-H functionalization cascades. Employing this silver-catalyzed oxidative strategy, common terminal alkynes were successfully converted into cyclopentenes via intermolecular [3 + 2] annulation

Metal-Free Oxidative Decarbonylative [3+2] Annulation of Terminal Alkynes with Tertiary Alkyl Aldehydes toward Cyclopentenes

A new metal-free oxidative decarbonylative [3+2] annulation of terminal alkynes with tertiary alkyl aldehydes is presented, which features broad substrate scope and excellent selectivity. The selectivity of this reaction toward cyclopentenes and indenes relies on the nature of the aldehyde substrates. While treatment of tertiary γ,δ-unsaturated aldehydes with common terminal alkynes assembles cyclopentenes, 2-methyl-2-arylpropanals succeed in accessing indenes

Rhodium-Catalyzed Synthesis of Isoquinolines and Indenes from Benzylidenehydrazones and Internal Alkynes

A new route is presented for the selective assembly of isoquinolines and indenes by rhodium-catalyzed tandem cyclization of benzylidenehydrazones with internal alkynes. This method involves the selective cleavage of the N–N bond and the CN bonds and is dependent on the substituents of the benzylidenehydrazone

Manganese-Catalyzed Intermolecular Oxidative Annulation of Alkynes with γ‑Vinyl Aldehydes: An Entry to Bridged Carbocyclic Systems

Manganese-catalyzed intermolecular oxidative annulation of alkynes with γ-vinyl aldehydes involving acylation and alkylation is described, thus providing a scenario for the divergent synthesis of bridged carbocyclic systems. By means of this manganese-catalyzed alkyne dicarbofunctionalization strategy, three chemical bonds, including two C–C bonds and one C–H bond, are formed via an aldehyde C­(sp²)–H oxidative functionalization/[4 + 2] annulation/protonation cascade

Metal-Free Oxidative 1,2-Arylmethylation Cascades of <i>N</i>‑(Arylsulfonyl)acrylamides Using Peroxides as the Methyl Resource

A new, metal-free oxidative 1,2-arylmethylation cascades of <i>N</i>-(arylsulfonyl)­acrylamides for the assembly of 2,2-disubstituted-<i>N</i>-arylbutanamides containing an all-carbon quaternary center is presented. This reaction enables the one-step formation of two new C–C bonds through a sequence of methylation/1,4-aryl migration/desulfonylation using an organic peroxide as the methyl resource with a broad substrate scope and excellent functional group tolerance

Visible-Light-Promoted Tandem Annulation of <i>N</i>‑(<i>o</i>‑Ethynylaryl)acrylamides with CH₂Cl₂

A novel tandem annulation of <i>N</i>-(<i>o</i>-ethyn­yl­aryl)­acryl­amides, with CH₂Cl₂ as a one-carbon unit, for the divergent synthesis of cyclopenta­[<i>c</i>]­quinolin-4­(<i>5H</i>)-ones and benzo­[<i>j</i>]­phenanthridin-6­(<i>5H</i>)-ones, which relies on the substitution effect of the 2 position of the acrylamide moiety, is described. Promoted by the visible-light photoredox catalysis, this reaction allows the formation of multiple chemical bonds through multiple C–Cl/C–H functionalization and [2 + 2 + 1] annulation cascades

Palladium-Catalyzed Oxidative Heck-Type Alkylation/Aryl Migration/Desulfonylation between Alkenes with α‑Carbonyl Alkyl Bromides

A new Pd­(II)-catalyzed alkene oxidative difunctionalization initiated by Heck insertion has been developed for the selective synthesis of acyclic and cyclic all-carbon quaternary stereocenters, which achieves an oxidative Heck-type alkylation, aryl migration, and desulfonylation sequence and represents a different input from those previously used Heck coupling in synthesis is reported

Sulfur Incorporation: Copper-Catalyzed Cascade Cyclization of 1,7-Enynes with Metal Sulfides toward Thieno[3,4‑<i>c</i>]quinolin-4(<i>5H</i>)‑ones

A novel copper-catalyzed cascade cyclization of 1,7-enynes with metal sulfides is described. This sulfur-incorporation method provides straightforward access toward the important thiophene-fused quinolin-4­(<i>5H</i>)-one scaffold through cyclization and double C–S bond formation cascade, and the chemoselectivity of this 1,7-enyne cyclization toward 1,3,3a,9b-tetrahydrothieno­[3,4-<i>c</i>]­quinolin-4­(<i>5H</i>)-ones and 3,3a-dihydrothieno­[3,4-<i>c</i>]­quinolin-4­(<i>5H</i>)-ones can be controlled by varying the sulfur resources

Complex Annulations through Silver Carbenoid Intermediate: An Alternative Entry to Transformations of 1,2,3-Triazoles

An alternative entry to transformations of <i>N</i>-sulfonyl-4-(2-(ethynyl)­aryl)-1,2,3-triazoles with various generated in situ or external nucleophiles by means of silver catalysis for producing diverse functionalized isoquinolines is described. Mechanistically, the reaction is proposed to involve a key silver carbenoid intermediate, thus enabling the formation of multiple chemical bonds via ring opening, N₂ extrusion, silver carbenoid formation, nucleophilic addition, and complex annulations cascades