Gold(III) Chloride Catalyzed Cyclization of α-Hydroxyallenes to 2,5-Dihydrofurans

reaction: see text Functionalized alpha-hydroxyallenes 1 were smoothly converted into the corresponding 2,5-dihydrofurans 2 by using 5-10 mol % of gold(III) chloride as catalyst. This mild and efficient cyclization method can be applied to alkyl- and alkenyl-substituted allenes at room temperature, furnishing tri- and tetrasubstituted dihydrofurans in good to excellent chemical yields and with complete axis to center chirality transfer.