The intramolecular aminoacylation of alkynes using ortho-alkynylacetanilides proceeds in very high yields in the presence of PtCl2 catalyst. This reaction provides not only a useful procedure for synthesizing 2,3-disubstituted indoles at once from ortho-alkynylaniline derivatives, but also an interesting mechanistic aspect; the intramolecular C-N bond addition of amides to alkynes takes place readily in the presence of Pt(II) catalyst.