Synlett 2008(16): 2400-2411  
DOI: 10.1055/s-2008-1078013
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© Georg Thieme Verlag Stuttgart ˙ New York

New Variation of the Aromatic ortho-Claisen Rearrangement: Synthesis of Fused Thiophenes and Pyrroles

Krishna C. Majumdar
Department of Chemistry, University of Kalyani, Kalyani 741235, India
e-Mail: kcm_ku@yahoo.co.in;
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Publikationsverlauf

Received 2 April 2008
Publikationsdatum:
31. Juli 2008 (online)

Abstract

The development of a new variation of the aromatic ortho-Claisen rearrangement of aryl propargyl sulfoxides and arylpropargylamine oxides involving tandem [2,3]- and [3,3]-sigmatropic rearrangements followed by ketolization/SN2′ displacement to give fused thiophenes and pyrroles, respectively, is described.

1 Introduction

2 The New Variant

3 Mechanism

4 Applications

4.1 Synthesis of Condensed Thiophenes

4.2 Synthesis of Bioactive Heterocycle-Annulated Thiophenes

4.3 Unusual Dehydrogenative Elimination

4.4 Aliphatic Counterpart of the Variant

5 Amine Oxide Counterpart of the Variant

6 Conclusion

35

Majumdar, K. C. unpublished results.