Dual Roles of β‑Oxodithioesters in the Copper-Catalyzed Synthesis of Benzo[<i>e</i>]pyrazolo[1,5‑<i>c</i>][1,3]thiazine Derivatives

A facile and efficient method for the chemoselective synthesis of benzo­[<i>e</i>]­pyrazolo­[1,5-<i>c</i>]­[1,3]­thiazine derivatives has been developed by tandem Ullmann coupling reactions of β-oxodithioesters (ODEs) with 3-(2-bromoaryl)-1<i>H</i>-pyrazoles in C–S bond formation manner, in which ODEs play dual roles as both a substrate and a ligand. A series of benzo­[<i>e</i>]­pyrazolo­[1,5-<i>c</i>]­[1,3]­thiazine derivatives were provided in good to excellent yields with CuI as the copper source in the presence of NaOH in CH₃CN at 80 °C under a N₂ atmosphere

Direct Construction of 2‑Aryliminochromenes from Arynes, <i>N</i>,<i>S</i>‑Keteneacetals, and DMF

A concise and direct synthetic strategy for the construction of 2-aryliminochromene skeleton by cascade three-component coupling reaction of arynes, <i>N</i>,<i>S</i>-keteneacetals, and DMF in good yields has been disclosed. The process demonstrates the first example of aryne chemistry combined with <i>N</i>,<i>S</i>-keteneacetals. Using this strategy, an expeditious synthesis of biologically important arylimino-2<i>H</i>-chromene-3- carboxamides was achieved

When Ethyl Isocyanoacetate Meets Isatins: A 1,3-Dipolar/Inverse 1,3-Dipolar/Olefination Reaction for Access to 3‑Ylideneoxindoles

A new CuI/1,10-phen-catalyzed reaction for the synthesis of 3-ylideneoxindoles from readily available isatins and ethyl isocyanoacetate, in which ethyl isocyanoacetate acts as a latent two-carbon donor like the Wittig reagent, is reported. A tandem procedure including 1,3-dipolar cycloaddition/inverse 1,3-dipolar ring opening/olefination allows the preparation of 3-ylideneoxindoles with broad functional group tolerance