Cu(OTf)2‑Catalyzed Synthesis of 2,3-Disubstituted Indoles and 2,4,5-Trisubstituted Pyrroles from α‑Diazoketones

A novel method has been devised for the synthesis of 2,4,5-trisubstituted pyrrole derivatives through the coupling of α-diazoketones with β-enaminoketones and esters using 10 mol % of Cu(OTf)2. A wide range of 2,3-disubstituted indole derivatives were also prepared from α-diazoketones and 2-aminoaryl or alkyl ketones. The synthetic versatility of this approach has been exemplified in the formal synthesis of homofascaplysin C.