title: Reaction of thioketones with propiolic acids.
abstract: The reaction of adamantane-2-thione with propiolic acid afforded a novel type of cycloadduct, spiro[adamantane-2,2'-6'H-[1,3]-oxathiin]-6'-one (3a), in quantitative yield. The reaction of thiobenzophenone with propiolic acid gave 2,2-diphenyl-6'H-[1,3]-oxathiin]-6'-one and 4-phenyl-3-thia-3,4-dihydronaphthoic acid in 34% and 35% yields, respectively. The reaction might proceed through a concerted process, as confirmed by kinetics. The reaction of adamantane-2-thione with 2-butynoic acid or phenylpropiolic acid gave the corresponding adducts regioselectively. Interestingly, only one isomer was obtained by the reaction of thiofenchone with propiolic acid, suggesting that the reaction proceeded diastereospecifically. Oxidation of adducts by dimethyldioxirane or m-chloroperoxybenzoic acid gave the corresponding sulfoxides and sulfones. The sulfoxides were thermally decomposed to give disulfide or another type of 1,3-oxathiin-6-one.
authors.affiliation: Department of Chemistry, Faculty of Science, Fukuoka University, Jonan-ku, Fukuoka, 814-0180, Japan. kokuma@fukuoka-u.ac.jp
authors.forename: Kentaro
authors.initials: K
authors.lastname: Okuma
authors.forename: Masahiro
authors.initials: M
authors.lastname: Koda
authors.forename: Shinobu
authors.initials: S
authors.lastname: Maekawa
authors.forename: Kosei
authors.initials: K
authors.lastname: Shioji
authors.forename: Tohru
authors.initials: T
authors.lastname: Inoue
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kurisaki
authors.forename: Hisanobu
authors.initials: H
authors.lastname: Wakita
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Yokomori
mesh_terms: D000218:Adamantane / Q000031:analogs & derivatives / Q000737:chemistry; D000480:Alkynes / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D015394:Molecular Structure; D011422:Propionates / Q000737:chemistry*; D013871:Thiones / Q000737:chemistry*
chemical_list: D000480:Alkynes; D007659:Ketones; D011422:Propionates; D013871:Thiones; C011537:propiolic acid; D000218:Adamantane