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Synfacts 2010(1): 0032-0032
DOI: 10.1055/s-0029-1218462
DOI: 10.1055/s-0029-1218462
Synthesis of Heterocycles
© Georg Thieme Verlag
Stuttgart ˙ New York
Acid-Mediated Synthesis of Benzofurans from Arylhydroxylamines
F. Contiero, K. M. Jones, E. A. Matts, A. Porzelle, N. C. O. Tomkinson*
Cardiff University, UK
Further Information
Publication History
Publication Date:
21 December 2009 (online)
Significance
Reported is the methanesulfonic acid mediated synthesis of benzofuran derivatives by aza-Cope rearrangement of hydroxylamine ethers generated from ketones and aromatic hydroxylamines. The reaction is potentially quite general in nature, as it proceeds predictably for the examples shown. In the case of 3,3,5,5-tetramethylhexanone, the reaction is low-yielding (30%) indicating the significance of steric effects, which is also demonstrated by the low yield (41%) of the 2-methylhexanone example. As an added bonus, the use of ketal A as starting material leads to a non-symmetrical dibenzofuran product. This last example merits further investigation.