Construction of intermediate 87 OH I(COCT)h, DMSO, CH2 Cl2, 1.Dba-H,CH2C2,-738"C 78°C, then Et,n 0 2. mCPBA,CHCl2,0°C CO,Et OTBS 2. Ph: P=CMeCO2Et, PhCO,H(cat ) PhH, 50 1. SO, pyr, Et N, DMSO 1.TBAF,THF,25℃C CH,Ch0C F 2. PPTS. CH,CI,.0 to 25C 2. PhaP=CH, THF.0C Ph (86% overall (81% overall) Only diasteromer observed 1.CSA(ceat.,MeOH0℃ 入oH1 KH, BnBr, THI,45℃ (95% FG 2.9-BBN,THF,25°C 2. i-BuMe, SiCl(2.5 equiv ) then Naoh,H2O2,0°C id,DMF,50°C 3.CSA(cat,MeOH,0°C 3.KH,BnB,THF,45℃ 4.(COCH, DMSO, CH2, (75% overall) 78°C, then et3N (81% for steps 2-4) F TBSO THF,0C(99%90Construction of Intermediate 87 1. (COCl)2 , DMSO, CH2Cl2 , -78 oC; then Et3N O O Ph H 133 Me O Me H OTBS F Me CO2Et O O Ph H 132 Me O Me H OTBS F OH 1. Dibal-H, CH2Cl2 , -78 oC 2. mCPBA, CH2Cl2 , 0 oC (94% overall) O O Ph H 134 Me O Me H O F TBS OH O Me 1. SO3 pyr., Et3N, DMSO, CH2Cl2 , 0 o O C O Ph H 135 Me O Me H O F TBS O Me 1. TBAF, THF, 25 oC 2. PPTS, CH2Cl2 , 0 to 25 oC (86% overall) O O Ph H 136 Me O Me H O F OH H Me 1. KH, BnBr, THF, 45 oC 2. 9-BBN, THF, 25 oC; then NaOH, H2O2 , 0 oC G O O Ph H 137 Me O Me H O F OBn H Me G OBn 2. Ph3P=CMeCO2Et, PhCO2H (cat.), PhH, 50 oC (86% overall) 2. Ph3P=CH2 , THF, 0 oC (81% overall) 3. KH, BnBr, THF, 45 oC (75% overall) 1. CSA (cat.), MeOH, 0 oC (95%) 2. t-BuMe2SiCl (2.5 equiv.), imid., DMF, 50 oC 3. CSA (cat.), MeOH, 0 oC 4. (COCl)2 , DMSO, CH2Cl2 , -78 oC; then Et3N (81% for steps 2-4) O TBSO H 105 Me O Me H O F OBn H Me G OBn TBSO PPh3 THF, 0 oC (99%) TBSO H 139 Me O Me H O F OBn H Me G OBn TBSO Only diasteromer observed