One-step synthesis of Ling's tetrol and its conversion into A,D-di-allo-α-cyclodextrin derivatives

2^A-F,3^B,C,E,F,6^B,C,E,F-Tetradeca-O-benzyl-α-cyclodextrin or Ling's tetrol is a unique α-cyclodextrin derivative that is partially protected with specific access points on both rims of the cyclodextrin structure. Ling's tetrol is therefore potentially useful for the synthesis of more complex and sophisticated enzyme models and supramolecular structures. However, the original synthesis gave only 10% yield after a reaction time of 4 days, and a recent improvement that gave 52% yield required two steps and a reaction time in one step of 6 days. Here, a single-step synthesis is reported where Ling's tetrol is obtained in a yield of 59% with a reaction time of 40 hours. 2^A-F,3^B,C,E,F,6^B,C,E,F-Tetradeca-O-benzyl-α-cyclodextrin was subsequently converted into 6^A,D-dicarboxy-3^A,D-diepi-α-cyclodextrin, 3^A,D-dioxo-α-cyclodextrin and 3^A,D-diamino-3^A,D-dideoxy-3^A,D-diepi-α-cyclodextrin. The binding of these compounds to CH₄ and CO₂ was determined.