title: Intramolecular [2+2+2] cycloaddition reactions of yne-ene-yne and yne-yne-ene enediynes catalysed by Rh(I): experimental and theoretical mechanistic studies.
abstract: N-tosyl-linked open-chain yne-ene-yne enediynes 1 and 2 and yne-yne-ene enediynes 3 and 4 have been satisfactorily synthesised. The [2+2+2] cycloaddition process catalysed by the Wilkinson catalyst [RhCl(PPh(3))(3)] was tested with the above-mentioned substrates resulting in the production of high yields of the cycloadducts. Enediynes 1 and 2 gave standard [2+2+2] cycloaddition reactions whereas enediynes 3 and 4 suffered β-hydride elimination followed by reductive elimination of the Wilkinson catalyst to give cycloadducts, which are isomers of those that would be obtained by standard [2+2+2] cycloaddition reactions. The different reactivities of these two types of enediyne have been rationalised by density functional theory calculations.
authors: Departament de Química, Universitat de Girona, Campus de Montilivi, s/n. 17071 Girona, Spain.
authors: Anna
authors: A
authors: Dachs
authors: Anna
authors: A
authors: Pla-Quintana
authors: Teodor
authors: T
authors: Parella
authors: Miquel
authors: M
authors: Solà
authors: Anna
authors: A
authors: Roglans