Activation of Carbonyl Groups and Alcohols

The gold catalyst has provided some very important achievements in chemistry in general, such as the asymmetric aldol reaction of aldehydes with isocyanoacetates reported by Ito, Sawamura and Hayashi [12,176]. The use of chiral ferrocenylpho-sphine gold (I) complexes allowed them to obtain enantiomerically-pure oxazo-lines. 

The substrate was cyclized to the oxazoline after aldol addition. This reaction generated such interest that it has been repeatedly reviewed since the 1990s [4, 177, 178]. 

The next milestone came with the description of the condensation reactions between 1,3- dicarbonyl compounds and alcohols, amines or thiol derivatives. This reaction was a great success in the search for simplicity as an efficient tool for green chemical processes, thanks to the reduction of the number of synthetic steps and 

Since then, similar reactions have been reported by different authors examples include the synthesis of quinolines [180] or even pyrroles [181] or enamines from chiral amines [182]. Indoles can also participate in these reactions [183]. 

In some cases, it was observed that Lewis acids could also activate the processes. However, AuCl3 displayed higher yields and higher selectivity [184]. 

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