title: Variants of the prins cyclization for the synthesis of terpenoid spiroethers and oxabicyclo[3.3.1]nonane derivatives.
abstract: Terpenoid spiroethers are abundant natural flavors with significant impact, particularly in the food industry. We present in this article the synthesis of new derivatives of the well-known flavors theaspirane and vitispirane using a variant of the Prins cyclization starting from α,β-unsaturated or heterocyclic ketones. When aromatic ketones were used as the starting materials for Lewis acid-mediated cyclizations, an alternative pathway involving a domino sequence of Prins cyclization, followed by an intramolecular Friedel-Crafts alkylation, gave benzoannelated oxabicyclo[3.3.1]nonane derivatives. Different reaction pathways may be triggered by the reaction temperature to give with good selectivity either tetrahydropyran derivatives as conventional Prins products or oxabicyclo[3.3.1]nonane derivatives.
authors.affiliation: University of Hamburg , Department of Chemistry, Pharmaceutical and Medicinal Chemistry, Bundesstrasse 45, 20146 Hamburg, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Weidmann
authors.forename: Jasper
authors.initials: J
authors.lastname: Ploog
authors.forename: Serge
authors.initials: S
authors.lastname: Kliewer
authors.forename: Mathias
authors.initials: M
authors.lastname: Schaffrath
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Maison
mesh_terms: D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003500:Cyclization; D004988:Ethers, Cyclic; D006571:Heterocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D007659:Ketones / Q000737:chemistry; D015394:Molecular Structure; D013141:Spiro Compounds; D013729:Terpenes / Q000737:chemistry*
chemical_list: C583524:2,8-dioxabicyclo(3.3.1)nonane; D019086:Bridged Bicyclo Compounds, Heterocyclic; D004988:Ethers, Cyclic; D006571:Heterocyclic Compounds; D007659:Ketones; D013141:Spiro Compounds; D013729:Terpenes; C531272:spiroether