title: A convenient approach to an advanced intermediate toward the naturally occurring, bioactive 6-substituted 5-hydroxy-4-aryl-1H-quinolin-2-ones.
abstract: 5-Hydroxy-4-aryl-3,4-dihydro-1H-quinolin-2-ones are a small family of natural products isolated from fungal strains of Penicillium and Aspergillus. Most of its members, which are insecticides and anthelmintics, carry an isoprenoid C-6 side chain. The synthesis of a 6-propenyl-substituted advanced intermediate for the total synthesis of these natural products is presented in this paper. This was achieved through the stereoselective construction of a β,β-diarylacrylate derivative from 6-nitrosalicylaldehyde, using a Wittig olefination and a Heck-Matsuda arylation, followed by a selective Fe(0)-mediated reductive cyclization. Installation of the 6-propenyl side chain was performed by 5-O-allylation of the heterocycle, followed by Claisen rearrangement and conjugative migration of the allyl double bond, as the key steps. The Grubbs II-catalyzed olefin cross metathesis of the 6-allyl moiety with 2-methylbut-2-ene to afford a precursor of peniprequinolone is also reported.
authors.affiliation: Instituto de Química Rosario (IQUIR, CONICET-UNR) and Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina. kaufman@iquir-conicet.gov.ar.
authors.forename: Sebastián O
authors.initials: SO
authors.lastname: Simonetti
authors.affiliation: Instituto de Química Rosario (IQUIR, CONICET-UNR) and Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina. kaufman@iquir-conicet.gov.ar.
authors.forename: Enrique L
authors.initials: EL
authors.lastname: Larghi
authors.affiliation: Instituto de Química Rosario (IQUIR, CONICET-UNR) and Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina. kaufman@iquir-conicet.gov.ar.
authors.forename: Teodoro S
authors.initials: TS
authors.lastname: Kaufman
mesh_terms: D001230:Aspergillus / Q000737:chemistry*; D001688:Biological Products / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D010407:Penicillium / Q000737:chemistry*; D015363:Quinolones / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D001688:Biological Products; D015363:Quinolones