Indole, alkyl-, reaction with carbenes

The intermediate carbenes generated from ketones and TMSC-(Li)N2 have also been shown to undergo 1,5 0-Si and N-H insertion to produce 5-trimethylsilyl-2,3-dihydrofurans and 2-pyrrolines or 3-substituted indoles, respectively (eqs 61 and 62). Azulene 1-carboxylic esters may be generated in moderate yield by the reaction of TMSC(Li)N2 with alkyl 4-aryl-2-oxobutanoates, followed by oxidation with manganese dioxide. ... 

Che has reported the tandem hydroamination/hydroarylation of aromatic amines wirh terminal alkynes to form dihydroquinolines in which 1 equiv of aniline combines with 2 equiv of alkyne [23]. For example, reaction of 3-methoxyanilme with pheny-lacetylene (5 equiv) and a catalytic 1 1 mixture of the gold(I) N-heterocydic carbene complex (IPr)AuCl (IPr= l,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidine) and AgOTf at 150 °C under microwave irradiation led to isolation of dihydroquinoline 21 in 82 % yield (Eq. (11.15)). Alternatively, reaction of o-acetylaniline with pheny-lacetylene catalyzed by a mixture of (IPr)AuCl and AgOTf at 150 °C led to isolation of the quinoline derivative 22 in 93% yield via incorporation of a single equivalent of alkyne (Eq. (11.16)). Arcadi has reported the gold(IlI)-catalyzed hydroamination/ hydroarylation of 2-alkynylanilines with a,p-enones to form C3-alkyl indoles [24]. As an example of this transformation, treatment of 2-(phenylethynyl)aniline with 4-phenyl-3-buten-2-one and a catalytic amount of sodium tetrachloroaurate dihydrate in ethanol at 30°C formed 1,2,3-trisubstituted indole 23 in 88% yield (Eq. (11.17)). 

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