Lithium tetrafluoroborate-assisted reactions of N-(.alpha.-aminoalkyl)benzotriazoles with olefins and 1,3-dienes. New syntheses of 1,2,5,6-tetrahydropyridinium salts, 1,2,3,4-tetrahydroquinolines, and some related heterocyclic systems
作者:Alan R. Katritzky、Mikhail F. Gordeev
DOI:10.1021/jo00067a043
日期:1993.7
Lithium tetrafluoroborate efficiently assists the ionization of N-(alpha-aminoalkyl)benzotriazoles in tetrahydrofuran solution to generate reactive iminium intermediates, which can be trapped with electron-rich olefins and with 1,3-dienes. Hetero Diels-Alder cycloadditions of N-(alpha-dialkylami-noalkyl)benzotriazoles and lithium tetrafluoroborate with 1,3-dienes thus gave 1,2,5,6-tetrahydropyridinium salts, while reactions of N-[alpha-(arylamino)alkyl]benzotriazoles with olefins and 1,3-dienes afforded substituted 1,2,3,4-tetrahydroquinolines, as well as examples of the new heterocyclic systems indeno[2,1-c]quinoline and pyrido[3,2,1-kl]-1,4-phenothiazine.