The first examples of Nazarov cyclizations leading to annulated pyrroles.
[reaction: see text] Reactions between alpha-substituted unsaturated carboxylic acids 20 and N-tosylpyrroles [14, 23] in the presence of trifluoroacetic anhydride result in smooth alpha-acylation of the pyrrole, followed by Nazarov cyclization to give 50-80% yields of cyclopenta[b]pyrroles. The presence of an alpha-substituent in the unsaturated acid appears to be mandatory.
Song
Chuanjun
C
School of Chemistry, Cardiff University, Main College, UK.
Knight
David W
DW
Whatton
Maria A
MA