4-Amino-1,2,4-triazoles-3-thiones and 1,3,4-oxadiazoles-2-thiones·palladium(II) recoverable complexes as catalysts in the sustainable Suzuki-Miyaura cross-coupling reaction

The Suzuki-Miyaura cross-coupling reaction using 4-amino-1,2,4-triazoles and 1,3,4-oxadiazoles-2-thiones·palladium (II) is studied. The reaction is optimized and the most appropriate catalytic complex is tested with several aryl halides, boronic acids in an environmentally benign solvent system (H2O/EtOH). The recovery of the catalytic species is also surveyed because of the nature of the employed solvent. A domino process is efficiently carried out following the standard conditions. Several surface parameters of the ligands are analyzed and the resulting values are extrapolated to the insoluble palladium catalyst.We gratefully acknowledge financial support from the Spanish Ministerio de Ciencia, Innovación y Universidades (projects CTQ2016-76782-P, CTQ2016-81797-REDC CTQ2016-81893REDT, and RED2018-102387-T) the Spanish Ministerio de Economía, Industria y Competitividad, Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER, EU) (projects CTQ2016-76782-P), the Generalitat Valenciana (PROMETEOII/2014/017), USTO-MB and the Universities of Mersin and Alicante. One of us (M.C.) thanks USTO-MB for scientific leave