An efficient catalytic protocol for the Pauson–Khand reaction

New experimental conditions have been developed for an efficient catalytic Pauson–Khand reaction. These are based on the use of a mixture of molecular sieves and tert-butanol as inducers of the process. This mixture, with the appearance of a paste, is able to adsorb CO, thus improving the conversion and making it possible to effect the reactions in the absence of a CO atmosphere. The protocol is applied to known and unknown substrates and compared to previously described conditions, showing good results with intra- and intermolecular examples.