A three-component domino reaction of 2-tetralone, hydroxylamine and acetylene: a one-pot, highly regioselective synthesis of 4,5-dihydrobenz[e]indoles

Synthesis of Highly Substituted Pyrroles via Nucleophilic Catalysis

“…A subsequent [3,3]-sigmatropic rearrangement forms 1,4-iminoaldehyde 4 , which upon cyclodehydration generates pyrrole 5 , in a manner analogous to the Paal-Knorr pyrrole synthesis . Importantly, this reaction provides (a) access to difficult to synthesize pyrroles from unactivated alkynes, and (b) a convergent way to form both a C−C bond and a C−N bond . Unfortunately, the usual reaction conditions are extremely harsh, requiring strong bases/high temperatures.…”