Organogolds halides

Phosphorus ylides react with organogold halides to give a variety of interesting structures whose thermal decomposition has been studied. The compound 52 is stable at its melting point of 205 °C but decomposes at higher temperatures with clean elimination of ethane to afford 5370. Bulky groups also lead to considerable stabilization and compounds such as 54 and 55 have decomposition temperatures above 150°C71. Finally, the cyclic compound 56 cleanly eliminates ethane at 153-155 °C to give 5772. 

Mixed-ligand anions [RC=CAuX] are rare in organogold chemistry. Selected examples have been obtained from reactions of [RC=CAuL oligomers with halides Q+X, from Q[Au(acac)2] salts with alkynes, followed by acids HX in the molar ratio 1 1 1, and from complexes (tht)AuCl (tht = tetrahydrothiophene) or [(Ph3P)2C]AuCl with an alkyne and a base (1 1 1). Known examples of products include salts Q+[HC=CAuCl/Br]-72 and [(Ph3P)2CH]+[PhC=CAuCl]. 52,53 Anions with mixed alkynyl/aryl substituents are present in... 

The cychc gold(I) phosphonium methylide heterocycles are the precursors for the few organogold(II) species reported. Oxidative addition (see Oxidative Addition) of halogen and alkyl halides leads to bicyclic compounds containing a transaimular Au Au bond (equations 28 and 29). These reactions are surprisingly facile and are now known to be... 

The pure and stable organogold (I) compounds, RAuL, can be prepared starting from a gold(I) halide-ligand complex ... 

Interestingly, only BiBrj gave quantitative yields of the products 416, while other bismuth(III) halides and Bi(OTf)3 had absolutely no effect for the reported transformation. The aUcenylbismuth derivatives could also be trapped in sUu with iodine or coupled with acyl chlorides in the presence of a palladium catalyst [119]. Addition of organogold compoimds to activated carbon-carbon triple bonds has also been reported to proceed under palladium catalysis [120]. Thus, (PhjPljPdClj or Pd2(dba)j complexes successfully promoted a regioselective syn carboauration of alkynes at ambient temperature (Scheme 10.143). 

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