Chemoselective Hydrogenation of Nitroarenes Catalyzed by Molybdenum Sulphide Clusters

• Published in: ChemCatChem 2017-03, Vol.9 (6), p.1128-1134
• Main Authors: Pedrajas, Elena, Sorribes, Iván, Gushchin, Artem L., Laricheva, Yuliya A., Junge, Kathrin, Beller, Matthias, Llusar, Rosa
• Format: Article
• Language: English
• Subjects: anilines; clusters; Hydrogenation; molybdenum; nitroarenes; sulfides
• ISSN: 1867-3880; 1867-3899
• DOI: 10.1002/cctc.201601496

Herein, we describe an atom efficient and general protocol for the chemoselective hydrogenation of nitroarenes to anilines catalyzed by well‐defined diimino and diamino cubane‐type Mo3S4 clusters. The novel diimino [Mo3S4Cl3(dnbpy)3]+ ([5]+) (dnbpy=4,4′‐dinonyl‐2,2′‐dipyridyl, L1) trinuclear complex was synthesized in high yields by simple ligand substitution reactions starting from the thiourea (tu) [Mo3S4(tu)8(H2O)]Cl4⋅4 H2O (3) precursor. This strategy has also been successfully adapted for the isolation of the diamino [Mo3S4Cl3(dmen)3](BF4) ([6](BF4)), (dmen=N,N′‐dimethylethylenediamine) salt. Applying these catalysts, high selectivity in the hydrogenation of functionalized nitroarenes has been accomplished. Over thirty anilines bearing synthetically functional groups have been synthesized in 70 to 99 % yield. Notably, the integrity of the cluster core is preserved during catalysis. Based on kinetic studies on the hydrogenation of nitrobenzene and other potential reaction intermediates, the direct reduction to aniline is the preferential route. Growing the molybdenum cluster age: Well‐defined diimino and diamino Mo3S4 cubane‐type clusters are applied as chemoselective catalysts for the hydrogenation of functionalized nitroarenes. This atom efficient procedure allows for the preparation of anilines bearing synthetically relevant functional groups in high yields.