Effective syntheses of per-2,3-di- and per-3-O-chloroacetyl-β-cyclodextrins: A new kind of ATRP initiators for star polymers

Selective chloroacetylations at per-2,3- and per-3-positions of β-cyclodextrin have been achieved via protection–deprotection methods. The reaction condition of pH >4 controlled by appropriate proton scavenger is essential for obtaining designed chloroacetylation degree under effective protection, as well as for high yield with less side-products. The β-cyclodextrin derivatives with 14 or 7 chloroacetyl groups are useful initiators for synthesizing star polymers with well-defined structure by atom transfer radical polymerization.