Substrate-Dependent Selectivity in Sc(OTf)3-Catalyzed Cyclization of Alkenoic Acids and N-Protected Alkenamides
Open Access
- 20 November 2022
- Vol. 12 (11) , 1481
Abstract
Five- and six-membered ring lactones and lactams are ubiquitous frameworks in various natural and synthetic molecules and are key building blocks in organic synthesis. Catalytic addition of an O-H or N-H bond across an unactivated C–C double bond is an appealing approach to rapidly access such highly valuable N- and O-containing skeletons in a waste-free and 100% atom efficient process. Herein, we report, for the first time, the efficient and high-yield cyclization of δ/ε-alkenoic acids and N-protected δ-alkenamides catalyzedby practical and easily accessible Lewis acid scandium(III) triflate under thermal and microwave conditions. The selectivity outcome of the reaction of δ/ε-alkenoic acids was dependent on the substitution patterns of the backbone chain and alkene moiety, leading to the exclusive formation of either the corresponding γ/δ-lactones via an O-selective cyclization or the Friedel–Crafts-type product by C-selective cyclization. An uncommon and rarely disclosed O-selective cyclization occurred preferentially or exclusively when N-protected δ-alkenamides were engaged in the reaction. The atom selectivity of the cyclization was unambiguously confirmed by single crystal X-ray crystallography.Keywords
This publication has 55 references indexed in Scilit:
- Kinetic Resolution of Racemic Carboxylic Acids through Asymmetric Protolactonization Promoted by Chiral Phosphonous Acid DiesterOrganic Letters, 2013
- Advances in the chemistry of ?-lactam and its medicinal applicationsTetrahedron, 2012
- Recent Advances in the Synthesis of α‐Alkylidene‐Substituted δ‐Lactones, γ‐Lactams and δ‐LactamsEuropean Journal of Organic Chemistry, 2011
- An Expedient Synthesis of Olfactory Lactones by Intramolecular Hydroacylalkoxylation ReactionsEuropean Journal of Organic Chemistry, 2011
- Aluminium(III) Trifluoromethanesulfonate as an Efficient Catalyst for the Intramolecular Hydroalkoxylation of Unactivated Olefins: Experimental and Theoretical ApproachesChemistry – A European Journal, 2006
- The Application of Transition Metal Catalysis for Selective Cyclocarbonylation Reactions. Synthesis of Lactones and LactamsSynlett, 2000
- (π-Allyl)tricarbonyliron Lactone Complexes in Organic Synthesis: A Useful and Conceptually Unusual Route to Lactones and LactamsChemical Reviews, 1996
- Synthesis and reactions of iodo lactamsThe Journal of Organic Chemistry, 1988
- A new .beta.-lactam synthesisJournal of the American Chemical Society, 1982
- Cyclic Quaternary Immonium Compounds Derived from 2,2-Diphenyl-4-pentenoic Acid1Journal of the American Chemical Society, 1952