The course of oxidative addition reactions of haloalkynes and haloalkenes to dimethyl- and dialkynylaurate(I) anions [RAuR]-

The reactions of halo-alkynes Cl-C CH, C-lCl C-Cl or PhC C-I with solutions of Li+[MeAuMe](-) in diethylether containing Ph3P do not give the expected oxidative addition products Me-2(RC C)Au(PPh3) with R = H, Cl, Ph. A mixture of other complexes is obtained instead which are generated in secondary reactions involving reductive elimination of ethane and/or dialkyne. However, addition of the halo-alkene H(Cl)C=CCl2, to the same substrate solution affords trans-Me-2[trans-H(Cl)C=C(Cl)]Au(PPh3) in good yield. Its molecular structure with pseudo-C-s symmetry has been determined by the solution NMR spectra and a single-crystal X-ray diffraction study. The reaction of methyl iodide with solutions of Li+[RC CAuC CR](-) in diethylether containing PPh3 give the quaternary salts Ph3PMe+. [RC CAuC CR](-) as the main products and only small amounts of cis-Me-2(RC C)Au(PPh3) complexes probably formed in a series of oxidative addition, reductive elimination, and substitution reactions. The structure of Ph3PMe+ [PhC CAuC CPh](-) has been determined. (c) 2006 Elsevier B.V. All rights reserved.