Intra- and intermolecular trapping of cyclopentapyrazine carbenes derived from 1,2-dialkynylimidazoles
作者:Asha K. Nadipuram、Sean M. Kerwin
DOI:10.1016/j.tetlet.2005.11.010
日期:2006.1
The thermolysis of 1,2-dialkynylimidazoles in benzene solution affords high yields of 7-pheiiyl-5H-cyclopentapyrazines, which presumably form by solvent trapping of cyclopentapyrazine carbene intermediates. In cases where dialkynylimidazole contains side chains that can participate in intramolecular carbene C-H insertion or olefin addition, these processes compete with solvent addition to afford novel tri- and tetracyclic pyrazines, which can be obtained in good yield when the thermolysis is carried out in hexafluoro benzene. (c) 2005 Elsevier Ltd. All rights reserved.