A new approach to the C_(28) fatty acid chain of the marine natural products schulzeines B and C: A concise diastereoselective total synthesis of(-)-schulzeine B

摘要

An enantioselective approach to the C_(28) fatty acid chain of the marine natural products schulzeines B and C was established based on the l-tartaric acid derived C_4 chiron 11 via successive 1,4-bis-chain elongation reactions and catalytic asymmetric hydrogenation. The chiral tricyclic core 8 was constructed via a diastereoselective Pictet-Spengler cyclization reaction (dr = 89:11) of the l-glutamic acid derived precursor 13. On this basis, a concise total synthesis of (-)-schulzeine B (5) was disclosed.