Arylcarboxylation/Cyclization/Hydrogenation Cascade of Arylalkynes with Formate: Synthesis of Ester-Substituted Dioxodihydrodibenzothiazepine Derivatives

Abstract A novel method has been developed for the arylcarboxylation/cyclization/hydrogenation cascade reaction of arylalkynes with cheap and readily available sodium formate (HCO2Na). This approach facilitates the efficient synthesis of ester-substituted dioxodihydrodibenzothiazepine derivatives in the absence of photocatalysts and transition metals. The methodology features a broad substrate scope, operational simplicity, excellent functional group tolerance, mild reaction conditions, and scalability. Mechanistic experiments proved that the reaction involves a pathway that includes the formation of the carbon dioxide radical anion (CO2•–) from formate. Meanwhile, the hydrogen in the product comes from trace amounts of water in the solvent or HCO2Na.