Divergent Synthesis of α,β -Unsaturated γ-Lactams via Tunable C–H Annulation of Acrylic Acids with Imines

Key Points

• The aim is to develop a tunable strategy for synthesizing α,β-unsaturated γ-lactams via C-H annulation.
• Utilized ruthenium-catalyzed redox-neutral vinylic C-H addition/cyclization.
• Employed in situ generated formaldimines for lactam synthesis.
• Explored higher temperatures for tandem C-H cyclization-vinylogous aldol-dehydration.
• Introduced rhodium catalysis to expand the reaction scope with substituted imines.
• Successfully synthesized α,β-unsaturated γ-lactams from acrylic acids and imines.
• Higher temperatures yielded methylene-γ-lactams via a different reaction pathway.
• Rhodium catalysis enabled the production of γ-substituted lactams, broadening synthetic options.