Silica supported phosphine gold complexes as an efficient catalytic system for a dearomative spirocyclization.

Silica supported phosphine gold complexes as an efficient catalytic system for a dearomative spirocyclization. Chemistry. 2020 Oct 16;: Authors: Cao Z, Scalabre A, Nlate S, Buffière S, Oda R, Pouget E, Bibal B Abstract The combination of metal catalyst and inorganic silica frames provides a greener approach for recyclable catalysis. Herein, chiral silica nanohelices were successfully employed to covalently graft three phosphine gold chloride complexes. The resulting 3D ensembles showed chiroptical properties that allowed the monitoring of the supported ligands. T he heterogeneous gold chloride catalysts in cooperation with silver triflate exhibited a high reactivity in various reactions, especially for the spirocyclization of aryl alkynoate esters when a catalytic loading of 0.05 %mol can be employed. The heterogeneous catalysts were easily recovered and can be recycled  up to 7-8 times without any loss of efficiency. By adding more silver triflate, 25 cycles with full conversion can be reached, due to a more  complex catalytic system based on silica and metallic species. PMID: 33064331 [PubMed - as supplied by publisher]
Source: Chemistry - Category: Chemistry Authors: Tags: Chemistry Source Type: research