Lc. Branco et Cam. Afonso, Ionic liquids as recyclable reaction media for the tetrahydropyranylation of alcohols, TETRAHEDRON, 57(20), 2001, pp. 4405-4410
A comparative study of the catalysed tetrahydropyranylation of 1-phenyletha
nol by p-toluenesulphonic acid (TsOH), pyridinium p-toluenesulphonate (PPTS
) and triphenylphosphine hydrobromide (TPP.HBr) using 3,4-dihydro-2H-pyran
in dichloromethane or in the ionic liquids 1-n-butyl-3-methylimidazolium te
trafluoroborate ([bmim][BF4]) or 1-n-butyl-3-methylimidazolium hexafluoroph
osphate ([bmim][PF6]) showed that the reaction occurs readily in [bmim][PF6
] for PPTS or TPP.HBr by a non-reversible process. These reaction media wer
e recycled on 22 occasions without loss of activity and their scope of appl
ication to other alcohols was also studied. (C) 2001 Elsevier Science Ltd.
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