Reaction of functionalized organolitihium compounds with substituted oxiranes: useful methodology for 1,6- and 1,7-diols, and tetrahydrobenzoxepines
Miguel Yus*, Tatjana Soler and Francisco Foubelo
*Departamento de Quimica Organica, Facultad de Ciencias, Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain, Email: yusua.es
M. Yus, T. Soler, F. Foubelo, Tetrahedron, 2002, 58, 7009-7016.
The reaction of dianions, derived from the reductive opening of phthalan (n=1) or isochroman (n=2) with lithium and a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB) at 0°C, with several epoxides gave 1,6- and 1,7-diols, respectively. Dehydration of the 1,6-diols by treatment with BF3ˇOEt2 in dichloromethane gave tetrahydrobenzoxepines in very good yields, whereas the 1,7-diols did not undergo dehydration.
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lithiation, oxiranes, addition, lithium, diols, oxepanes, benzo-fused O-heterocycles