Llorente V. R. Bonaga

Synthesis of medium-sized rings using the intramolecular Pauson–Khand reaction

Abstract The dicobalthexacarbonyl alkyne complex of a series of enynes templated on aromatic rings has been shown to undergo the Pauson–Khand reaction to generate medium-sized rings.

Modification and limitations of the Livinghouse catalytic Pauson-Khand reaction

Abstract The difficult and impractical purification of Co 2 (CO) 8 is not necessary in the catalytic thermal Pauson-Khand reaction previously described by Livinghouse.

Catalyst precursors for the catalytic Pauson-Khand reaction

Dicobalt hexacarbonyl complexes of enynes serve as Co2(CO)8 surrogates for the intramolecular Pauson-Khand cycloaddition. Enynes with polar functional groups allow for easy separation of the catalyst cyclopentenone by-product (acid or base wash, silica gel plug column) from the desired cyclopentenone.

DIENES FROM THE THERMOLYSIS OF DICOBALTHEXACARBONYL-COMPLEXED ENYNES : MECHANISTIC INSIGHT

Abstract Thermolysis of the hexacarbonyldicobalt complex of 1,6- or 1,7-enynes yields monocyclic 1,3-dienes. Deuterium labeling studies rule out an α-elimination as the mechanistic pathway for diene formation.

Aqueous-phase, thermal Pauson-Khand reactions in the presence of surfactants

Abstract Efficient stoichiometric Pauson–Khand reactions were realized in water as the only solvent, and in the presence of surfactants as additives. Use of the cationic surfactant CTAB provided good yields of cyclopentenones from the thermal reactions of pre-formed dicobalthexacarbonyl complexes of enynes and alkynes. The water-CTAB medium was found to be less effective with Co 4 (CO) 12 as the promoter of the reaction. Incidentally, these results have provided a strictly water-based PKR protocol under very mild and convenient conditions.

Catalytic activity of dodecacarbonyltetracobalt in aqueous media: a “greening” of the Pauson–Khand reaction

The unprecedented reactivity of Co(4)(CO)(12) with enynes under aqueous conditions, representing the development of a mild and simple aqueous-phase cobalt-catalyzed PK reaction protocol, is described herein.