title: Exploring O-stannyl ketyl and acyl radical cyclizations for the synthesis of γ-lactone-fused benzopyrans and benzofurans.
abstract: The synthesis of a series of γ-lactone-fused benzopyrans and benzofurans, analogues of the pyranonaphthoquinone antibiotics, is reported. Preparation of the heterocycles was achieved by either O-stannyl ketyl or acyl radical cyclization of benzaldehyde precursors followed by oxidation to give the pyrano- and furanobenzoquinone systems. The observed diastereoselectivity during O-stannyl ketyl radical cyclization is influenced by aromatic substitution ortho to the aldehyde, whilst acyl radical cyclization followed by stereoselective reduction of the resulting pyranones provides a complimentary approach to forming the required γ-lactone-fused benzopyran systems.
authors.affiliation: ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, Australia. cdonner@unimelb.edu.au.
authors.forename: Helen
authors.initials: H
authors.lastname: Santoso
authors.forename: Myriam I
authors.initials: MI
authors.lastname: Casana
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Donner
mesh_terms: D001572:Benzofurans / Q000138:chemical synthesis* / Q000737:chemistry; D001578:Benzopyrans / Q000138:chemical synthesis* / Q000737:chemistry; D003500:Cyclization; D005609:Free Radicals / Q000138:chemical synthesis / Q000737:chemistry; D007783:Lactones / Q000737:chemistry*; D015394:Molecular Structure
chemical_list: D001572:Benzofurans; D001578:Benzopyrans; D005609:Free Radicals; D007783:Lactones