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New synthesis of methyl 5-aryl or heteroaryl pyrrole-2-carboxylates by a tandem Sonogashira coupling/5-endo-dig-cyclization from β-iododehydroamino acid methyl esters and terminal alkynes
- Source :
-
Tetrahedron . Nov2008, Vol. 64 Issue 47, p10714-10720. 7p. - Publication Year :
- 2008
-
Abstract
- Abstract: A new and versatile ‘Pd’/CuI catalyzed protocol was developed for the synthesis in good to high yields of substituted pyrroles from N-Boc-β-iododehydroamino acid methyl esters and several terminal alkynes. This one-pot, two-step procedure occurs by a Sonogashira coupling followed by a 5-endo-dig-cyclization, which involves the nitrogen atom of the dehydroamino acid. After several experiments using different Pd(0) and Pd(II) species it was possible to establish the more general reaction conditions, which are: the use of a Pd(II) catalyst, CuI and Cs2CO3 as base in dry DMF at 70°C. The best yields were obtained with arylacetylenes bearing electron-donating groups and with electron-rich heteroarylacetylenes. [Copyright &y& Elsevier]
- Subjects :
- *ORGANONITROGEN compounds
*NITROGEN compounds
*ORGANIC compounds
*OXIMES
Subjects
Details
- Language :
- English
- ISSN :
- 00404020
- Volume :
- 64
- Issue :
- 47
- Database :
- Academic Search Index
- Journal :
- Tetrahedron
- Publication Type :
- Academic Journal
- Accession number :
- 34742909
- Full Text :
- https://doi.org/10.1016/j.tet.2008.08.105