| The first enantioselective total synthesis of the proposed structure of aldingenin B is reported in sixteen longest linear steps from known compounds. The stereochemistry at C5 and C6 were established by an asymmetric acetal aldol. Following a ring-closing metathesis, a selective, substrate-controlled hydrogen bond-mediated dihydroxylation provided control of the C2 and C3 stereocenters. Other key reactions include a cycloketalization, a bromoetherification, and two cerium trichloride promoted nucleophilic additions. Discrepancies in the spectroscopic data of the synthetic and natural material led to the conclusion that the structure of the natural sample was misassigned. |
