C-H functionalization of cyclic amines: redox-annulations with α,β-unsaturated carbonyl compoundsElectronic supplementary information (ESI) available: Experimental procedures and characterization data. CCDC 1061074 and 1061075. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5cc03390j

Cyclic amines such as pyrrolidine and 1,2,3,4-tetrahydroisoquinoline undergo redox-annulations with α,β-unsaturated aldehydes and ketones. Carboxylic acid promoted generation of a conjugated azomethine ylide is followed by 6π-electrocylization, and, in some cases, tautomerization. The resulting ring-fused pyrrolines are readily oxidized to the corresponding pyrroles or reduced to pyrrolidines. Pyrrolidine and related amines undergo carboxylic acid promoted redox-annulations with α,β-unsaturated ketones via the intermediacy of conjugated azomethine ylides.