Pyrroles as C-nucleophiles in reactions with acylacetylenes
摘要:
The reactions of substituted pyrroles with terminal acylacetylenes occur selectively to form 2-(Z/E-2-acylvinyl)pyrroles. When the reactions are performed on the surface of silica gel, C-vinylation is noticeably accelerated to form predominantly E-isomers. ESR spectroscopy with the use of a spin trap demonstrated the ion-radical character of the process. The structures of the adducts synthesized, which exist as anti-s-cis- and syn-s-cis-rotamers, were studied by IR, UV, and NMR spectroscopy.