title: Reactions of cycloaliphatic thioketones and their oxo analogues with lithiated methoxyallene: a new approach to vinylthiiranes.
abstract: Admantanethione smoothly reacted with lithiated methoxyallene at low temperatures yielding the expected allenyl-substituted thiolate, which upon aqueous work-up underwent spontaneous 1,3-cyclization to afford a hitherto unknown methoxy-substituted vinylthiirane derivative. The analogous reaction with adamantanone led to the corresponding allenyl alcohol that can be isolated and--depending on the conditions applied--either be converted into the corresponding vinyloxirane or into the 2,5-dihydrofuran derivative. Sterically more crowded thioketones were also combined with lithiated methoxyallene, but in these cases competitive 1,5-cyclization leading to isomeric dihydrothiophene derivatives was observed. DFT calculations of model intermediates and products show distinct energy differences of the sulfur and the corresponding oxygen compounds. Desulfurization of the adamantanethione-derived vinylthiirane yielded a methoxy-substituted 1,3-diene that was studied in cycloadditions with electron-deficient dienophiles. Whereas in the case of tetracyanoethylene the corresponding cyclobutane derivative was formed, the reaction with nitrosobenzene provided the expected 1,2-oxazine derivative. By reductive cleavage of the N-O bond this heterocycle was converted into an unsaturated amino alcohol bearing an adamantane moiety.
authors.affiliation: Department of Organic and Applied Chemistry, University of Łódź, Tamka 12, 91-403 Łódź (Poland), Fax: (+48) 42-665-51-62; Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin (Germany). mjasinski@uni.lodz.pl.
authors.forename: Marcin
authors.initials: M
authors.lastname: Jasiński
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Mlostoń
authors.forename: Michał
authors.initials: M
authors.lastname: Stolarski
authors.forename: Wilhelmine
authors.initials: W
authors.lastname: Costa
authors.forename: Moises
authors.initials: M
authors.lastname: Domínguez
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Reissig
keywords: alkoxyallenes; desulfurization; thiiranes; thioketones; thiophenes