Three-component domino process for the pyrrolizine skeleton via [3 + 2]-cycloaddition-enamine cyclization triggered
Kenji Sugimoto1, Nozomi Yamamoto, Daisuke Tominaga
1Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama , 2630 Sugitani, Toyama 930-0194, Japan.
Abstract:
Pyrrolizines are bicyclic fused azaheterocycles with a bridgehead nitrogen contained in a core skeleton and are often found in biologically active compounds. Despite their importance, there have been few reports on concise and flexible syntheses of pyrrolizines. A novel one-pot, convergent method is described for pyrrolizines by simple mixing of iminoesters, acetylenes, and dipolarophiles in the presence of a cationic gold catalyst and an acid additive. This domino process affords multisubstituted pyrrolizines without handling unstable intermediates.
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