6533b857fe1ef96bd12b4e41

RESEARCH PRODUCT

Capping α-Cyclodextrin with Cyclotriveratrylene by Triple Disulfide-Bridge Formation

subject

description

Disulfide-bond formation is an expeditious coupling reaction to make macropolycyclic symmetrical receptors. It is used here for the preparation of unsymmetrical cavitands based on α-cyclodextrin (α-CDX) and cyclotriveratrylene (CTV) analogues. Accordingly, diastereomeric hemicryptophanes 2a and 2b were obtained in 11 % isolated yield by the iodine oxidation of a 1:1 mixture of racemic cyclotrithiophenolene (3) and the C3-symmetric trithiol derivative of permethylated α-cyclodextrin (PM α-CDX) 4. Remarkably, the target hemicryptophanes were obtained in a 5:3 diastereomeric ratio. The reaction produced mainly (34 %) a singly disulfide-bridged PM α-CDX dimer 7, however no traces of triply disulfide-bridged head-to-head PM α-CDX dimer were detected. In addition, the formation of the known S-cryptophane-0.0.0 was observed.