Formal Total Synthesis of Stevastelins B and B3

The formal total synthesis of stevastelins B and B3 (2 and 4, resp.) have been accomplished employing a highly enantiomerically controlled Lewis acid catalyzed non-aldol approach to obtain the syn aldol product and temperature controlled hydroboration oxidation reaction to construct four consecutive stereogenic centers. The other key reactions include Sharpless asymmetric epoxidation, macrolactonization, and macrolactamization towards building the core skeleton 2 and 4.