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

Abstract

The reactions of halo-alkynes Cl–C CH, C–lC C–Cl or PhC C–I with solutions of Li +[MeAuMe] − in diethylether containing Ph 3P do not give the expected oxidative addition products Me 2(RC C)Au(PPh 3) 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 CCl 2 to the same substrate solution affords trans-Me 2[ trans-H(Cl)C C(Cl)]Au(PPh 3) 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 PPh 3 give the quaternary salts Ph 3PMe + [RC CAuC CR] − as the main products and only small amounts of cis-Me 2(RC C)Au(PPh 3) complexes probably formed in a series of oxidative addition, reductive elimination, and substitution reactions. The structure of Ph 3PMe + [PhC CAuC CPh] − has been determined.