title: Preparation of Tremorine and Gemini Surfactant Precursors with Cationic Ethynyl-Bridged Digold Catalysts.
abstract: Tremorine and precursors of gemini surfactants were synthesised in a one-pot, three-step, double-catalytic A3coupling reaction and characterised by structural and spectroscopic methods. The cationic [AuI(L1)]SbF6complex is a more active catalyst compared to neutral L2- and L3-AuIbis(trifluoromethanesulfonyl)imidate complexes (L1, L2=Buchwald-type biaryl phosphane; L3=triphenylphosphine) in promoting the double A3coupling of ethynyltrimethylsilane, secondary amines (cyclic, aliphatic, or aromatic) and formaldehyde. The solvent influences the catalytic performance by desilylation of silyl acetylene or deactivation of the catalyst by a halide anion. Acetylide-bridged cationic digold(I) L1 and L2 complexes were isolated and characterised by means of single-crystal X-ray structure analysis and their spectroscopic properties. Iodine in the acetylene reagent deactivates the AuIcatalyst by formation of the less active iodido-bridged cationic digold(I) L1 complex, which was fully characterised by single-crystal X-ray crystal structure analysis and spectroscopy. The nature of the phosphine ligand of the gold complexes used as catalyst affects the stability and activity of the formed cationic ethynyl-bridged AuI2-L intermediates, isolation of which lends support to the proposed double A3coupling mechanism.
authors.affiliation: Instituto Universitario de Tecnología Química CSIC-UPV, Universitat Politècnica de València, Av. De los Naranjos s/n, 46022, Valencia, Spain.
authors.forename: Abdessamad
authors.identifier: http://orcid.org/0000-0001-5388-3554
authors.initials: A
authors.lastname: Grirrane
authors.affiliation: Departamento de Química Inorgánica, Instituto de Investigaciones Químicas CSIC-US, Av. Américo Vespucio 49, 41092, Sevilla, Spain.
authors.forename: Eleuterio
authors.identifier: http://orcid.org/0000-0002-8378-8459
authors.initials: E
authors.lastname: Álvarez
authors.affiliation: Instituto Universitario de Tecnología Química CSIC-UPV, Universitat Politècnica de València, Av. De los Naranjos s/n, 46022, Valencia, Spain.
authors.forename: Hermenegildo
authors.identifier: http://orcid.org/0000-0002-9664-493X
authors.initials: H
authors.lastname: García
authors.affiliation: Instituto Universitario de Tecnología Química CSIC-UPV, Universitat Politècnica de València, Av. De los Naranjos s/n, 46022, Valencia, Spain.
authors.forename: Avelino
authors.identifier: http://orcid.org/0000-0002-2232-3527
authors.initials: A
authors.lastname: Corma
keywords: alkyne ligands; gold; homogeneous catalysis; multicomponent reactions; phosphane ligands