1. E. Baciocchi, S. Clementi, and G. V. Sebastiani, J. Chem. Soc. Perkin Trans. II, 266 (1976).
2. Identification of the addition products formed in the chlorination of benzofuran
3. The glc analysis of the reaction mixture shows the presence of benzofuran, 3-bromobenzofuran, 3-chlorobenzofuran, and 2-chlorobenzofuran. The absence of the peak of 2-bromo-benzofuran is a clear evidence of the complete absence of I in the reaction mixture, as the latter is known to give, by thermal decomposition, an appreciable amount (25%) of 2-bromoderivative, together with 70% of IV and 5% of III. The relative amount of benzofuran (25%), 2-chlorobenzofuran (40%), and 3-chlorobenzofuran (35%) is in agreement with the pattern obtained by thermal decomposition of an authentic specimen of trans- 2,3-dichloro-2,3-dihydrobenzofuran. On the other hand the nmr spectrum of the reaction product is compatible with that previously reported for the latter compound (2).
4. W. H. Saunders Jr., and A. F. Cockerill, “Mechanisms of Elimination Reactions”, New York, N.Y., 1973, p. 194 ff.
5. E. Baciocchi and L. Mandolini, Tetrahedron Letters, 1659 (1971).