Ozawa T, Aoyagi S, Kibayashi C
School of Pharmacy, Tokyo University of Pharmacy & Life Science, Horinouchi, Hachioji, Tokyo 192-0392, Japan.
J Org Chem. 2001 May 18;66(10):3338-47. doi: 10.1021/jo001589n.
The first syntheses of (-)-lepadins A and C, as well as a new synthesis of (-)-lepadin B, have been achieved from commercially available (S)-malic acid. The methodology is based on an intramolecular hetero-Diels--Alder reaction of the acylnitroso compound, affording the bicyclic oxazino lactam with trans selectivity, which was converted to the cis-decahydroquinoline via asymmetric enolate hydroxylation followed by intramolecular aldol cyclization. The total syntheses proceed by employing cis-decahydroquinoline bearing the (E)-iodoalkenyl group as the common key intermediate, which underwent a convergent coupling with the (E)-hexenyl unit via a palladium-catalyzed Suzuki cross-coupling reaction for the elaboration of the octadienyl side chain at the C5 position.
已从市售的(S)-苹果酸出发，首次完成了(-)-勒帕定A和C的合成，以及(-)-勒帕定B的新合成。该方法基于酰基亚硝基化合物的分子内杂Diels-Alder反应，以反式选择性得到双环恶嗪内酰胺，通过不对称烯醇盐羟基化，然后进行分子内羟醛环化，将其转化为顺式十氢喹啉。全合成通过使用带有(E)-碘代烯基的顺式十氢喹啉作为共同关键中间体进行，该中间体通过钯催化的铃木交叉偶联反应与(E)-己烯基单元进行汇聚偶联，以构建C5位的八烯基侧链。
