Condensed Heteroaromatic Ring Systems. XII. Synthesis of Indole Derivatives from Ethyl 2-Bromocarbanilates
The palladium-catalyzed reaction of ethyl 2-bromocarbanilate with trimethylsilylacetylene yielded ethyl 2-(trimethylsilylethynyl)carbanilate, which was treated with sodium ethoxide to give indole.The carbanilates having a methyl or a bromo substituent were similarly transformed to corresponding indole derivatives.Furthermore, pyrrolo- and Pyrrolopyridines were synthesized by this method.Keywords---palladium-catalyzed reaction; trimethylsilylacetylene; ethyl 2-halocarbanilate; ethyl 2-halopyridinecarbamate; ethyl 2-(trimethylsilylethynyl)carbanylate; ethyl o-(trimethylsilylethynyl)pyridinecarbamate;indole;pyrrolopyridine