Palladium-Catalyzed Carbonylative Annulation Reactions Using Aryl Formate as a CO Source: Synthesis of 2‑Substituted Indene-1,3(2<i>H</i>)‑dione Derivatives

An efficient synthesis of 2-substituted indene-1,3­(2<i>H</i>)-diones from stable and readily available 1-(2-halophenyl)-1,3-diones by employing phenyl formate as a CO source has been developed. The reaction occurred via palladium-catalyzed intramolecular carbonylative annulation using K₃PO₄ as a base and DMSO as a solvent at 95 °C. In this protocol, the reaction showed a broad substrate scope with good to excellent yields

Palladium-Catalyzed Synthesis of α‑Iminonitriles from Aryl Halides via Isocyanide Double Insertion Reaction

An efficient one-pot synthesis of α-iminonitriles from readily available aryl halides via palladium-catalyzed double isocyanide insertion and elimination has been developed, without using various hypertoxic cyanides and excess oxidants. Furthermore, the utility of this reaction was demonstrated by the rapid total synthesis of quinoxaline and the reaction of functional groups exchanged with aryl halides

Cu-Mediated Stereoselective [4+2] Annulation between <i>N</i>‑Hydroxybenzimidoyl Cyanide and Norbornene

A Cu-mediated stereoselective [4+2] annulation between <i>N</i>-hydroxybenzimidoyl cyanides and norbornene (NBE) has been developed for the synthesis of 4<i>H</i>-1,2-oxazin-4-ones. The reaction proceeds through sequentially forming C–O/C–C bonds. The advantage of this reaction includes high stereoselectivity, excellent yields, as well as simple and mild reaction conditions. A total of 26 examples are presented along with some control experiments