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

The reactions of halo-alkynes Cl–Ctriple bond; length of mdashCH, C–lCtriple bond; length of mdashC–Cl or PhCtriple bond; length of mdashC–I with solutions of Li+[MeAuMe]− in diethylether containing Ph3P do not give the expected oxidative addition products Me2(RCtriple bond; length of mdashC)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)Cdouble bond; length as m-dashCCl2 to the same substrate solution affords trans-Me2[trans-H(Cl)Cdouble bond; length as m-dashC(Cl)]Au(PPh3) in good yield. Its molecular structure with pseudo-Cs 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+[RCtriple bond; length of mdashCAuCtriple bond; length of mdashCR]− in diethylether containing PPh3 give the quaternary salts Ph3PMe+ [RCtriple bond; length of mdashCAuCtriple bond; length of mdashCR]− as the main products and only small amounts of cis-Me2(RCtriple bond; length of mdashC)Au(PPh3) complexes probably formed in a series of oxidative addition, reductive elimination, and substitution reactions. The structure of Ph3PMe+ [PhCtriple bond; length of mdashCAuCtriple bond; length of mdashCPh]− has been determined.