Carbocyclization of d-glucose: syntheses of gabosine I and streptol

d-Glucose was differentially protected with a trans-diacetal at C-2,3, an ethoxymethyl ether at C-4, and a tert-butyldimethylsilyl ether at C-6, and then carbocyclized via a key Horner–Wadsworth–Emmons (HWE) olefination to give a versatile synthetic intermediate, enone 13, which was readily transformed into gabosine I and streptol.