title: Rhodium(I)-catalysed intramolecular [2+2+2] cyclotrimerisations of 15-, 20- and 25-membered azamacrocycles: experimental and theoretical mechanistic studies.
abstract: A new series of 20- and 25-membered polyacetylenic azamacrocycles have been satisfactorily prepared and completely characterised by spectroscopic methods. Various [2+2+2] cyclotrimerisation processes catalysed by the Wilkinson's catalyst, [RhCl(PPh(3))(3)], were tested in the above-mentioned macrocycles. The 25-membered azamacrocycle (like the previously synthesised 15-membered azamacrocyle) led to the expected cyclotrimerised compound in contrast to the 20-membered macrocycle, which is characterised by its lack of reactivity. The difference in reactivity of the 15-, 20- and 25-membered macrocycles has been rationalised through density functional theory calculations.
authors.affiliation: Institut de Química Computacional and Departament de Química, Universitat de Girona, Campus de Montilivi, 17071 Girona, Spain.
authors.forename: Anna
authors.initials: A
authors.lastname: Dachs
authors.forename: Anna
authors.initials: A
authors.lastname: Torrent
authors.forename: Anna
authors.initials: A
authors.lastname: Roglans
authors.forename: Teodor
authors.initials: T
authors.lastname: Parella
authors.forename: Sílvia
authors.initials: S
authors.lastname: Osuna
authors.forename: Miquel
authors.initials: M
authors.lastname: Solà