Enantioselective Synthesis of Schulzeines B and C via a β-Lactone-Derived Surrogate for Bishomoserine Aldehyde
摘要:
Enantioselective syntheses of the glucosidase inhibitors schulzeines B and C were achieved by employing a Pictet-Spengler reaction of a beta-lactone-derived masked bishomoserine aldehyde. Subsequent Corey-Link reaction unveiled an alpha-azido acid enabling cyclization to the delta-lactam fused tetrahydroisoquinoline. An efficient synthesis of the trisulfate-bearing side chain featured a Noyori hydrogenation and a Sharpless dihydroxylation. An unexpected reaction of a pendant amine during a Corey-Link process opens avenues for the synthesis of proline and related amino acid derivatives.
A new approach to the C28 fatty acid chain of the marine natural products schulzeines B and C: a concise diastereoselective total synthesis of(−)-schulzeine B
the marine natural products schulzeines B and C was established based on the l-tartaric acid derived C4 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