作者:M. S. Novikov、A. F. Khlebnikov、E. S. Sidorina、A. E. Masalev、J. Kopf、R. R. Kostikov
DOI:10.1023/a:1019659021891
日期:——
Difluoro(iminio)methanides generated by the action of difluorocarbene on Schiff bases react with derivatives of maleic and fumaric acids, following the 1,3-dipolar cycloaddition pattern to give 2,2-difluoropyrrolidines which were detected by gas chromatography-mass spectrometry. The final products are stereoisomeric substituted 2-pyrrolidinones formed by hydrolysis of difluoropyrrolidines and their dehydrofluorination products, 2-fluoro-4,5-dihydropyrroles. The observed stereoselectivity of the cycloaddition suggests Z configuration of intermediate ylide and both endo- and exo-approach to the dipolarophile in the transition state corresponding to cycloaddition.
Generation and 1,3-dipolar cycloadditions of fluorine-containing azomethine ylides derived from difluorocarbene and imines
作者:Mikhail S. Novikov、Alexander F. Khlebnikov、Alexander E. Masalev、Rafael R. Kostikov
DOI:10.1016/s0040-4039(97)00872-1
日期:1997.6
Iminiodiflouromethanides, generated by the reaction of difluorocarbene with N-benzylidene amines, undergo 1,3-dipolar cycloaddition to electron-deficient alkenes to give pyrrolidine derivatives in moderate to good yields.