Loss of allyl cation configuration in cycloadditions to electron-rich conjugated dienes

D I Rawson, B. K. Carpenter, H. M R Hoffmann

Research output: Contribution to journalArticle

Abstract

The cycloaddition of W-configurated 1,3-dimethyl-2-oxyallyl cations to electron-rich cyclic conjugated dienes is accompanied by configurational losses and leads to cycloadducts with a,ß-configurated (equatorial, axial) methyl groups. For aromatic "dienes" such as benzene and N-alkylpyrroles, clectrophilic substitution competes strongly with [4 + 3 ? 7] cycloaddition which, nonetheless, can be accomplished by choice of an oxyallyl moiety with the proper blend of electrophilicity and nucleophilicity. It is suggested that formation of the seven-membered ring proceeds in two distinct stages, i.e., the stepwise pull-push mechanism involving formation of the first s bond in an electrophilic step and the second s bond in a nucleophilic step. © 1979 American Chemical Society.

Original languageEnglish
Pages (from-to)1786-1793
Number of pages8
JournalJournal of the American Chemical Society
Volume101
Issue number7
Publication statusPublished - 1979

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    Rawson, D. I., Carpenter, B. K., & Hoffmann, H. M. R. (1979). Loss of allyl cation configuration in cycloadditions to electron-rich conjugated dienes. Journal of the American Chemical Society, 101(7), 1786-1793.