An enantioselective total synthesis of (+)-lepadin F is described. The synthetic sequence features an intermolecular aza-[3 + 3] annulation, homologation of a vinylogous amide via Eschenmoser's episulfide contraction, and a highly stereoselective hydrogenation essential for achieving the 1,3-anti relative stereochemistry at C2 and C8a.
An enantioselective total synthesis of (+)-lepadin F is described. The synthetic sequence features an intermolecular aza-[3 + 3] annulation, homologation of a vinylogous amide via Eschenmoser's episulfide contraction, and a highly stereoselective hydrogenation essential for achieving the 1,3-anti relative stereochemistry at C2 and C8a.
Assignment of the C5′ Relative Stereochemistry in (+)-Lepadin F and (+)-Lepadin G and Absolute Configuration of (+)-Lepadin G
作者:Gang Li、Richard P. Hsung
DOI:10.1021/ol9018997
日期:2009.10.15
Concise assignments of the C5' stereochemistry in (+)-lepadin F and (+)-lepadin G and the absolute configuration of (+)-lepadin G via the first total syntheses of (+)-5'-epi-lepadin F, (+)-lepadin G, and (+)-5'-epi-lepadin G are described. This work represents an Illustrative example in which a diastereomeric pair can possess sufficient spectroscopic difference for clear assignment despite differing only at a highly insulated acyclic stereocenter.