A Novel Access to Ionone-Type Compounds: (E)-4-Oxo-β-ionone and (E)-4-Oxo-β-irone via Metal-Catalyzed, Intramolecular Reactions of α-Diazo Ketones with Furans

Article abstract of DOI:10.1002/hlca.19890720416

(E)-5-Demethyl-4-oxo-β-ionone (2), (E)-4-oxo-β-ionone (3), (E)-4-oxo-β-irone (4), and the five-membered ring analogs 36-41 were synthesized by a novel, convergent route starting from 2-methylfuran (1).A recently discovered, intramolecular reaction of 2-(diazoacyl)furans, catalyzed by dirhodium tetraacetate, leading to diene-diones served as key step, thereby testing its utility in natural-product synthesis for the first time.