A recoverable Pd nanocatalyst for selective semi-hydrogenation of alkynes: hydrogenation of benzyl-propargylamines as a challenging model

Abstract

We describe a recyclable heterogeneous palladium nanocatalyst for the selective hydrogenation of alkynes to alkenes. The catalyst was prepared through the decomposition of the organometallic precursor Pd2(dba)3 over a magnetic support, obtaining well-dispersed Pd nanoparticles that formed exclusively on the support surface, with average diameters of 3.5 ± 0.8 nm. The catalytic activity was evaluated in the hydrogenation reactions of alkenes and alkynes, and the chemo- and stereoselectivity was evaluated in the hydrogenation of benzylpropargylamines. The catalyst is highly selective in performingsemi-hydrogenation reactions under mild conditions and short reaction times, with good overall yields. Furthermore, it can be easily recovered and recycled, with no leaching of palladium detected, and it can retain high activities and selectivity over multiple reaction cycles.