Total Synthesis of the Marine Alkaloids (−)-Lepadins A, B, and C Based on Stereocontrolled Intramolecular Acylnitroso-Diels−Alder Reaction
作者:Tetsuji Ozawa、Sakae Aoyagi、Chihiro Kibayashi
DOI:10.1021/jo001589n
日期:2001.5.1
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
(-)-lepadins A和C的第一个合成,以及(-)-lepadin B的新合成,已经从市售(S)-苹果酸中获得。该方法基于酰基亚硝基化合物的分子内杂Diels-Alder反应,可提供具有反式选择性的双环恶嗪内酰胺,可通过不对称烯醇化羟基化反应随后转化为顺式十氢喹啉,然后进行分子内羟醛环化反应。通过使用带有(E)-碘链烯基的顺式十氢喹啉作为共同的关键中间体进行总合成,该中间体通过钯催化的Suzuki交叉偶联反应与(E)-己烯基单元进行收敛偶联,以精制C5位置的辛二烯基侧链。