Third generation Retrosynthetic approach TBSO 1: brevetoxin B 85 EFGThird Generation Retrosynthetic Approach O O O O O O O O O O O O O Me H H H H H H Me H H H HO H Me H H Me Me H H H Me Me A B C D E F G H I J K 1: brevetoxin B O O O O O O O O O O OTPS Me H H H H H H Me H H H TBSO H Me H H Me Me EtS H Me Me A B C D E F G I J K EtS HO 85 O O O O O O O Me H H H H H H Me H Me H H Me Me Me A OTMS PPh3 O O O H H OTBS EtS H Me I EtS H H O J K OTPS + 87 86 B C D E F G