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DOI: 10.1055/s-2003-39411
N- and C-Vinylation of Pyrroles with Disubstituted Activated Acetylenes
Publication History
Received
3 March 2003
Publication Date:
26 May 2003 (online)


Abstract
Addition of pyrrole and 2-phenylpyrrole to 2-acyl- and 2-cyano-1-phenylacetylenes in the KOH-DMSO system affords chemo- and regioselectively N-adducts: 1-(2-acyl- and 1-(2-cyano-1-phenylethenyl)pyrroles in 32-89% yield. 4,5,6,7-Tetrahydroindole reacts with 2-cyano-1-phenylacetylene analogously. Unexpectedly, with 2-benzoyl-1-phenylacetylene, the reaction follows mainly the C-vinylation route to give (E,Z)-2-(2-benzoyl-1-phenylethenyl)-4,5,6,7-tetrahydroindole and cyclo-bis-adduct, 2-(2-benzoyl-1,3-diphenyl-1,4,5,6,7,8-hexahydrocyclopenta[b]indol-1-yl)-1-phenylethanone, a product of intramolecular cyclization of 2,3-di(2-benzoyl-1-phenylethenyl)-4,5,6,7-tetrahydroindole.
Key words
pyrroles - alkynes - alkenation - chemoselectivity - regioselectivity - cyclizations - indoles