Construction of intermediate 87 10% Pd/C(cat) TBSO Na,cO. EtOAc 2. CSA(I equiv ) CH,Ch MeOH,0°C (95% overall 2, 4, 6-ClC6H,COCI 1.(COCi)2, DMSO, CH2Cl EtN,THF,0℃C 78°c, then EtN then4DMAP,PhH,80℃C 2. NaCIO, NaH, PO 4 (90%0) 3. TBAF THF 65C (88%overall) LIN(SIMe3h, HMPA THF78° C then phntf E 78to25℃C(93%)TBSO H 139 Me O Me H O F OBn H Me G OBn TBSO 1. H2 , 10% Pd/C (cat.), Na2CO3 , EtOAc 2. CSA (1 equiv.), CH2Cl2 , MeOH, 0 oC (95% overall) TBSO H 140 Me O Me H O F OBn H Me G OBn HO 1. (COCl)2 , DMSO, CH2Cl2 , -78 oC, then Et3N 2. NaClO2 , NaH2PO4 3. TBAF, THF, 65 oC (88% overall) HO H 141 Me O Me H O F OBn H Me G OBn HO O 2,4,6-Cl3C6H2COCl, Et3N, THF, 0 oC; then 4-DMAP, PhH, 80 oC (90%) H 104 Me O Me H O F OBn H Me G O OBn O E LiN(SiMe3 )2 , HMPA, THF, -78 oC; then PhNTf2 , -78 to 25 oC (93%) H 102 Me O Me H O F OBn H Me G O OBn TfO E Construction of Intermediate 87