Supported gold nanoparticles catalyzed cis-selective semihydrogenation of alkynes using ammonium formate as the reductant

Abstract

TiO₂ supported gold nanoparticles with low loading (0.5 mol%) are able to semihydrogenate non-fluorinated and gem-difluorinated alkynes to cis-alkenes with high selectivity, using cost-effective and easy-to-handle ammonium formate as the reductant. No over-reduction was observed. The good recyclability of Au/TiO₂ allows for “green” semireduction of alkynes. A difluorinated pyran and α,β-unsaturated δ-lactone were easily prepared from the obtained gem-difluoro alkene building blocks.