2,3-Difunctionalized Indoles via Radical Acylation or Trifluoromethylation of ortho -Alkynylphenyl Isonitriles.

A radical cascade to 2,3-disubstituted indoles proceeding via acylation or trifluoromethylation of ortho -alkynylphenyl isonitriles is presented. In these cascades, two C-C bonds and one C-O bond are formed using an inexpensive oxidant and a catalytic copper or iron salt. The starting isonitriles are easily accessible, and commercially available aldehydes and fluoromethylation reagents serve as reaction partners. Functional group tolerance is high, as documented by the successful preparation of a series of 2,3-disubstituted indoles.