2003 Benzofuran derivatives

Benzofuran derivativesR 0070 Reactions of o-Quinones with α-Methyl- (or Methylene) Substituted Phosphorus

Ylides. Synthesis of Benzo[b]furan Derivatives. — The Wittig reaction ofo-quinones (I), (VI), and (VIII) with ylides (II), (X), (XIII) and (XV) yields o-vinylphe-nols and/or benzofurans as main products. In the reaction of (VIII) with (X), the unex-pected compound (XII) is formed besides the known furan derivative (XI). A deviation of the normal Wittig reaction is observed during the reaction of (VIII) with (XIII). The benzofurans are obtained via cyclization of the o-vinylphenols initially formed by tautomerization of the Wittig monoolefination products. The o-vinylphenols can be used as synthons for a variety of further transformations due to their easy prep-aration in one step in moderate to good yields. — (GAUTAM, D. R.; LITINAS, K. E.; FYLAKTAKIDOU, K. C.; NICOLAIDES*, D. N.; J. Heterocycl. Chem. 40 (2003) 3, 399-404; Lab. Org. Chem., Aristotle Univ., GR-54006 Thessaloniki, Greece; Eng.) — H. Hoennerscheid

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