The three isomeric mono-2-, 3- or 6-hydroxy permethylated β-cyclodextrins are good precursors for a wide variety of mono functionalised 'permethyl' β-cyclodextrins. In this work, we describe the selective access to mono-6-hydroxy (via the mono-6-tertbutyldimethylsilyl derivative), mono-2-hydroxy (via the mono-2-benzyl derivative) and mono-3-hydroxypermethylated-β-cyclodextrins (by under-methylation of heptakis (2,6-di-O-methyl)-β-cyclodextrin). These derivatives were characterised by high field 1 H and 1 3 C NMR spectroscopy. The position of the free hydroxyl group was confirmed unambiguously by 1 3 C NMR after methylation with 1 3 C-labelled methyl iodide.