title: Radical photocyclization route for macrocyclic lactone ring expansion and conversion to macrocyclic lactams and ketones.
abstract: A new method for the synthesis of macrocyclic lactones, lactams, and ketones, which utilizes photoinduced intramolecular radical cyclization reactions of substrates containing tethered carboxylic acids and α,β-unsaturated carbonyl moieties, has been uncovered. Photocyclization of the carboxylic acids tethered acrylate ester, which were prepared starting from the macrocyclic lactones, gave the two-carbon elongated macrocyclic lactones via decarboxylation. Similar photoreactions of carboxylic acid tethered acryl amide or α,β-unsaturated ketone moieties, which were also prepared starting from the macrocyclic lactones, produced macrocyclic lactams or ketones, respectively. The simple approach can be readily applied to the preparation of a variety of macrocyclic lactones, lactams, and ketones with tunable ring sizes.
authors.affiliation: Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Nishikawa
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Yoshimi
authors.forename: Kousuke
authors.initials: K
authors.lastname: Maeda
authors.forename: Toshio
authors.initials: T
authors.lastname: Morita
authors.forename: Ichiro
authors.initials: I
authors.lastname: Takahashi
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Itou
authors.forename: Sho
authors.initials: S
authors.lastname: Inagaki
authors.forename: Minoru
authors.initials: M
authors.lastname: Hatanaka
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D007659:Ketones / Q000138:chemical synthesis* / Q000737:chemistry*; D047029:Lactams, Macrocyclic / Q000138:chemical synthesis* / Q000737:chemistry*; D007783:Lactones / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D010777:Photochemistry
chemical_list: D002264:Carboxylic Acids; D007659:Ketones; D047029:Lactams, Macrocyclic; D007783:Lactones