Fluorinated alcohol directed formation of dispiro-1,2,4,5-tetraoxanes by hydrogen peroxide under acid conditions
2005; Elsevier BV; Volume: 62; Issue: 7 Linguagem: Inglês
10.1016/j.tet.2005.11.022
ISSN1464-5416
AutoresKatja Žmitek, Stojan Stavber, Marko Zupan, Danièle Bonnet‐Delpon, Jernej Iskra,
Tópico(s)Porphyrin and Phthalocyanine Chemistry
ResumoThe oxidative system MTO/30%H2O2/HBF4/fluorous alcohol is promising for the selective synthesis of biologically important antimalarial dispiro-1,2,4,5-tetraoxanes by direct acid-catalysed cyclisation of various 4-substituted cyclohexanones (1, R=Me, Et, tBu, Ph, COOEt, CF3). The role of the substitutent at the 4-position was important in the selectivity of formation of tetraoxane (2, TO) with respect to hexaoxonane (3, HO). By the use of fluorinated alcohols and under the right reaction conditions, tetraoxanes 2 were selectively formed and synthesised in 46–86% isolated yield from 4-substituted cyclohexanones 1.
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