The role of bromoalkanes on the catalytic activation of carbon-supported gold nanoparticles for hydration of terminal alkynes

We here report that traces of long-chain bromoalkanes can activate carbon-supported Au(0) nanoparticles (NPs) for terminal alkyne hydration to methylketones. This AuNP-bromoalkane system is effective for both aliphatic and aromatic substrates, yielding high Markovnikov product selectivity (up to 93%). Hot filtration tests and the absence of leached Au suggest surface-bound Au NPs drive the catalytic activity. The catalyst is easily recoverable and reusable for several recycle runs. Overall, the findings presented in this contribution reveal the noninnocent role of bromine-containing impurities, underscoring the importance of their careful consideration when evaluating the activity of Au-based catalytic systems.