Construction of intermediate 87 Continued 1.Li,NH3①,-78° OBn 2. p-TsCl, pyr, CH2Cl2, 25C OBn (73% overall Me159 1. Nal, (CH3)2C0, 60C Meo、MeH 2. TMS-imidazole, CH2Cl2, 25C E 3PhP,CH3CN80°C 0 E AB Key Intermediate 87O O O O O O O Me H H H H H H Me H Me H H Me Me Me A B C D E F G OBn OBn H 159 O O O O O O O Me H H H H H H Me H Me H H Me Me Me A B C D E F G OH OTs H O O O O O O O Me H H H H H H Me H Me H H Me Me Me A B C D E F G OTMS PPh3 I 160 1. Li, NH3 (l), -78 oC 2. p-TsCl, pyr., CH2Cl2 , 25 oC (73% overall) 1. NaI, (CH3 )2CO, 60 oC 2. TMS-imidazole, CH2Cl2 , 25 oC 3. Ph3P, CH3CN, 80 oC (92% overall) Key Intermediate 87 Construction of Intermediate 87 Continued