title: Aluminium complexes derived from tridentate thioetherbis(phenolate) ligands and their activity in Diels-Alder catalysis.
abstract: Organoaluminium(III) thioetherbis(phenolate) complexes derived from 2,2-thiobis(4,6-diterbuthylphenolate) (Stdiol) and 2,2-thiobis(4,6-dimethylphenolate) (Smdiol) were prepared by reaction of AlMe3 with the diol proligands LH2 (SmdiolH2, StdiolH2). Monomeric complexes of general formulae [LAlR(L)] (L = Stdiol, R = Me, L = THF (1); L = Stdiol, R = Me, L = Et2O (2); L = Stdiol, R = iBu, L = THF) (3); L = Smdiol, R = Me, L = THF (4); L = Smdiol, R = iBu, L = THF (5)) and [LAlCl(THF)] (L = Stdiol (6); L = Smdiol (7)) were obtained when the reactions were performed in THF or Et2O in hexane or toluene, species of formulae [(L2Al)AlR2] (L = Stdiol, R = Me (8); L = Stdiol, R = iBu (9); L = Smdiol, R = Me (10)) were formed as evidenced by spectroscopic methods. Crystals suitable for X-ray diffraction studies were obtained for 2, 3, 4, 6, 8, 9 and 10. In these cases the sulfur atom coordinates to the aluminium center with Al-S bond lengths between 2.43-2.75 A adopting boat-boat conformations. Compounds 1, 3, 4, and 8 were tested in the catalytic Diels-Alder cycloaddition reaction between methacrolein and cyclopentadiene showing excellent regioselectivities with good conversion yields.
authors.affiliation: Av. Universidad 1001, Col. Chamilpa, Cuernavaca, Morelos 62209, Mexico.
authors.forename: Norma
authors.initials: N
authors.lastname: Tiempos-Flores
authors.forename: Alejandro-José
authors.initials: AJ
authors.lastname: Metta-Magaña
authors.forename: Virginia
authors.initials: V
authors.lastname: Montiel-Palma
authors.forename: Sara-Angélica
authors.initials: SA
authors.lastname: Cortés-Llamas
authors.forename: Miguel-Angel
authors.initials: MA
authors.lastname: Muñoz-Hernández