β-cyclodextrin as supramolecular catalyst in organic synthesis

Abstract

(A) Oxiranes react smoothly with thiourea in the presence of β-cyclodextrin in water at room temperature under neutral conditions to afford the corresponding thiiranes in excellent yields and β-cyclodextrin was recycled. (B) A facile, substrate-selective and transition-metal-free oxidation of benzylic and allylic alcohols catalyzed by β-cyclodextrin with NaOCl oxidant using water as only solvent was developed. (C) Recently, the bridged keto cyclodextrins were used for oxidation of alcohols to aldehydes in the presence of hydrogen peroxide in aqueous media at room temperature. (D) Mononitroarenes are reduced to azooxyarenes by NaOH in water in the presence of β-cyclodextrin. HO- acts as a one-electron reductant with enhanced reactivity. (E) The one-pot synthesis of terephthalic acid from benzene has COOH been achieved by treatment with tetrachloromethane, copper powder, and an aqueous sodium hydroxide solution using cyclodextrin as a catalyst at 30 °C under nitrogen with 100% selectivity. (F) The hydrolysis of tetrahydropyranyl ethers to alcohols catalysed by β-cyclodextrin proceeds in water under neutral conditions. © Georg Thieme Verlag Stuttgart.