A compound of formula: wherein R1 is hydrogen or a hydroxyl protecting group and R2 and R3 are same or different and are independently selected from halogen or - O - SO2 - X wherein X is C1 - C4 alkyl C1 - C4 alkyl substituted with one or more halogen or substituted or unsubstituted phenyl wherein said phenyl substituent is selected from halogen, nitro and C1 - C4 alkyl provided that when R3 is bromine, X is not p-tolyl and a process for the preparation thereof.一種具有如下分子式的化合物:其中R1是氫或羥基保護基;以及R2以及R3是相同或不同的,且獨立地選自鹵素或-O-SO2-X;其中X是C1-C4烷基;以一或更多個鹵素取代的C1-C4烷基;或取代或未取代的苯基,其中所述苯基取代基選自鹵素、硝基以及C1-C4烷基;前提是當R3是溴時,X不是對甲苯基;以及一種用於該化合物之製備的方法。
