Organogolds reactions with

The reaction with active methylene compounds results in the hydrogen abstraction to give the alcohol and the organogold derivatives.178... 

Addition of CI2 to organogold(I) complexes has also been achieved by reaction with thallium(III) chloride [Eq. (47)] (13, 36, 180-182), the cis isomers being produced by this method. Reactions with X2 gave the trans isomers (179). 

Organogold(I) complexes undergo a number of insertion reactions with unsaturated molecules, such as olefins, acetylenes, and sulfur dioxide. Insertion of carbon monoxide or carbon dioxide has not been achieved, although the reverse reaction has been observed with C02 (7/). 

There now exists a large number of methods for the synthesis of organogold complexes with various ylide ligands. In an extensive reaction chemistry, successive oxidation of the gold centres [Au(I) -> Au(II) Au(III)] can often be accomplished. Ylide complexes of gold have therefore been summarized in the following sections regardless of their oxidation state. 

The same effect has been observed in the case of an encapsulated organogold catalyst of cycloi-somerization of enyne 441 by Scheme 5.23, and it has been attributed [22] to the hydrophobic environment within the coordination capsule 575, preventing carbenium-ionic intermediates of the catalytic process from their side reactions with water. The same caging catalyst has been used in [23] to perform the combined enzymatic and transition metal catalysis of tandem reactions by Scheme 5.24. The authors of this work also developed a tandem olefin isomerization-reduction reaction by Scheme 5.25 with the encapsulated organoruthenium cation as a catalyst on its... 

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... 

Carbenes are defined as molecular species with formally divalent and two-coordinate carbon atoms bearing various substituents X and Y and a lone pair of electrons. While the simple representatives are of low stability (such as CH2) and may only appear as short-lived reaction intermediates or in adducts with electron donors, some cyclic systems can be readily isolated. This is particularly true for many of the A-heterocyclic carbenes (NHCs), which are now widely applied as ligands to metals ( Wanzlick-Arduengo carbenes ). Such carbenes based on imidazol and benzimidazol have become the working horses in this branch of organogold chemistry (Scheme 54). 

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