title: Experimental evidence for the involvement of dinuclear alkynylcopper(I) complexes in alkyne-azide chemistry.
abstract: Dinuclear alkynylcopper(I) ladderane complexes are prepared by a robust and simple protocol involving the reduction of Cu(2)(OH)(3)OAc or Cu(OAc)(2) by easily oxidised alcohols in the presence of terminal alkynes; they function as efficient catalysts in copper-catalysed alkyne-azide cycloaddition reactions as predicted by the Ahlquist-Fokin calculations. The same copper(I) catalysts are formed during reactions by using the Sharpless-Fokin protocol. The experimental results also provide evidence that sodium ascorbate functions as a base to deprotonate terminal alkynes and additionally give a convincing alternative explanation for the fact that the Cu(I)-catalysed reactions of certain 1,3-diazides with phenylacetylene give bis(triazoles) as the major products. The same dinuclear alkynylcopper(I) complexes also function as catalysts in cycloaddition reactions of azides with 1-iodoalkynes.
authors.affiliation: Department of Chemistry, Loughborough University, Loughborough, Leicestershire, LE11 3TU UK.
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Buckley
authors.forename: Sandra E
authors.initials: SE
authors.lastname: Dann
authors.forename: Harry
authors.initials: H
authors.lastname: Heaney