Nucleophilic Additions to Triazolinedione Ylides, ExtremelyReactive Carbonyl Equivalents: A New Class of Condensation Reactions
Journal of Organic Chemistry
The ylides of N-phenyltriazolinedione (10 and 13) are readily prepared when the ylide carbon atom is substituted by phenyl or 3-methylindol-2-yl groups. In fact the indole-substituted ylide 10 is sufficiently stabile to be isolated in good yield when it is formed by the oxidation of the corresponding urazole 9 with tert-butyl hypochlorite followed by dehydrohalogenation with triethylamine. These triazolinedione ylides both undergo facile addition of nucleophiles at the ylide carbon atoms. In the case of nucleophilic addition by enolate species, the initial adducts undergo subsequent elimination of N-phenylurazole to form olefinic condensation products, while nucleophilic addition of pyrrole or n-butanethiol results in bis adducts in which two molecules of the nucleophile become attached to what had been the ylide carbon atom. The in situ generation of these triazolinedione ylides and subsequent transformations are operationally extremely simple procedures that frequently afford high product yields and as such would seem to offer considerable promise as synthetic methods.
R. M. Wilson and A. C. Hengge. “Nucleophilic Additions to Triazolinedione Ylides, Extremely Reactive Carbonyl Equivalents: A New Class of Condensation Reactions.” Journal of Organic Chemistry, 1987, 52, 2699-2707.