Hydroamination gold catalysis

In recent years, several groups have developed enantioselective tandem reactions based on the combination of gold catalysis and organocatalysis. Among them, Gong et al. reported that an achiral gold complex compatibly worked with a chiral phosphoric acid to promote a domino intramolecular hydroamination-reduction reaction, readily transforming... 

Scheme 7.30 Domino intramolecular hydroamination-reduction reaction catalysed by chiral phosphoric acid catalysis and gold catalysis.

Later, an enantioselective one-pot tandem Mannich-hydroamination reaction was reported by Liu and co-workers on the basis of a sequential organo- and gold catalysis.The proeess involved propargylated malonitrile and oxindole imine derivatives as substrates and employed a chiral cinchona alkaloid, such as a quinidine phenol derivative, to induce the enantioselective Mannich reaction and a gold catalyst, such as XPhosAuNTfa... 

Tandem Mannich-type-hydroamination-isomerisation catalysed by chiral thiourea catalysis and gold catalysis. 

Scheme 7.64 Tandem nitro-Mannich-hydroamination-isomerisation reaction catalysed by chiral urea catalysis and gold catalysis.

Scheme 7.65 Tandem Mannich-hydroamination reaction catalysed 1 chiral cinchona alkaloid catalysis and gold catalysis.

Scheme 7.67 Tandem hydroamination-hydroarylation-transfer hydrogenation reaction catalysed by gold catalysis and chiral phosphoric acid...

By combining an initial gold-catalyzed hydroaminative indole formation with repetitive hydroarylations, Hirano et al. [48] reported the gold-catalyzed direct construction of highly fused carbazoles by multiple cyclization. Scheme 4.28 shows one example of this chemistry, and the overall yield of this pentacyclization is excellent, highlighting the efficiency of gold catalysis. 

In 2010, Wang et al. applied the gold(I)/chiral Brpnsted acid relay catalysis to a novel three-component cascade reaction, providing direct access to structurally diverse julolidine derivatives 374 in high optical purity (Scheme 2.99). The phosphoric acid (Se)-catalyzed asymmetric Povarov reaction of 2-(2-propynyl)anihnes 365, (V-vinylcarbamate 8, and aldehydes 3 provided enantioenriched tetrahydroquinoline intermediates 372, which then underwent a hydroamination reaction under the catalysis of a gold complex to give julolidine derivatives with up to >99% ee [133]. 

Han Z-Y, Xiao H, Chen X-H, Gong L-Z. Consecutive intramolecular hydroamination/asymmetric transfer hydrogenation under relay catalysis of an achiral gold complex/chiral brpnsted acid binary system. J. Am. Chem. Soc. 2009 131 9182-9183. 

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