| Abstract
| - A variety of gold(I) complexes containing the water-soluble phosphine ligands TPPMS, TPPDS, andTPPTS (mono-, di-, and tri-sulfonated triphenylphosphine, respectively) were tested as catalysts for thehydration of phenylacetylene in aqueous media. The gold(I) alkynyl complexes [AuC⋮CR(TPPTS)] (whereR = tBu and 3-thiophenyl) give the highest ever reported turnover frequencies (1000 and 1060 h-1,respectively) for the hydration of phenylacetylene under optimum conditions (0.1 mol % catalyst loading,10 mol % H2SO4, 1 h reflux in 5:1 MeOH/H2O). The hydration of phenylacetylene can also be carriedout using only water and reaction medium, which allows recycling of the gold catalyst without significantdrop of activity for at least three cycles. DFT calculations were used to compare relative energies ofpossible intermediates involved in the catalytic cycle.
- The hydration of phenylacetylene and other alkynes in an acidic, aqueous medium catalyzed by various water-soluble organometallic gold(I) complexes was studied. Kinetic and mechanistic data was obtained experimentally and from computational results to explain some of the trends observed. With the optimum catalyst under optimized conditions, the so far highest ever reported turnovers for the hydration of phenylacetylene were obtained.
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