Gold(I) Catalysis Applied to the Stereoselective Synthesis of Indeno[2,1-b]thiochromene Derivatives and Seleno Analogues

A gold(I)-catalyzed cascade reaction for the stereoselective synthesis of sulfur- or selenium-containing indeno[1,2-b]chromene derivatives from o-(alkynyl)styrenes substituted at the triple bond with a thio- or seleno-aryl group is described. The reaction involves a double cyclization process through a proposed key gold−cyclopropyl carbene intermediate that evolves by the intramolecular addition of an aromatic to the cyclopropane ring, affording polycyclic structures. The enantioselective version was studied using gold(I) complexes bearing chiral ligands.We gratefully acknowledge MICINN (PID2020-115789GBC21), “NextGenerationEU/PRTR” (PDC2021-120825-C21), Junta de Castilla y León, and FEDER (BU049P20) for financial support. The project leading to these results also received funding from the “la Caixa” Foundation, under Agreement LCF/PR/PR18/51130007 (CAIXA-UBU001). C.V. and S.S.-P. thank Junta de Castilla y León (Consejería de Educación) and Fondo Social Europeo for postdoctoral contracts