title: Chiral transition-metal complexes as Brønsted-acid catalysts for the asymmetric Friedel-Crafts hydroxyalkylation of indoles.
abstract: The Friedel-Crafts reaction between 3,3,3-trifluoropyruvates and indoles is efficiently catalysed by the iridium complex [(η(5)-C5Me5)Ir{(R)-Prophos}(H2O)][SbF6]2 (1) with up to 84% ee. Experimental data and theoretical calculations support a mechanism involving the Brønsted-acid activation of the pyruvate carbonyl by the protons of the coordinated water molecule in 1. Water is not dissociated during the process and, therefore, the catalytic reaction occurs with no direct interaction between the substrates and the metal.
authors.affiliation: Instituto de Síntesis Química y Catálisis Homogénea, Universidad de Zaragoza-Consejo Superior de Investigaciones Científicas, Pedro Cerbuna 12, 50009 Zaragoza, Spain. dcarmona@unizar.es.
authors.forename: Daniel
authors.initials: D
authors.lastname: Carmona
authors.forename: M Pilar
authors.initials: MP
authors.lastname: Lamata
authors.forename: Antonio
authors.initials: A
authors.lastname: Sánchez
authors.forename: Fernando
authors.initials: F
authors.lastname: Viguri
authors.forename: Ricardo
authors.initials: R
authors.lastname: Rodríguez
authors.forename: Luis A
authors.initials: LA
authors.lastname: Oro
authors.forename: Chunhui
authors.initials: C
authors.lastname: Liu
authors.forename: Silvia
authors.initials: S
authors.lastname: Díez-González
authors.forename: Feliu
authors.initials: F
authors.lastname: Maseras