Asymmetric Synthesis of (−)-Eburnamonine and (+)-<i>e</i><i>pi</i>-Eburnamonine from (4<i>S</i>)-4-Ethyl-4-[2-(hydroxycarbonyl)ethyl]-2-butyrolactone
作者:Andrew G. H. Wee、Qing Yu
DOI:10.1021/jo010751z
日期:2001.12.1
The key chiral nonracemic 4,4-disubstituted 2-butyrolactone carboxylic acid, (S)-4, is readily accessible via an efficient and stereospecific dirhodium(II) tetraacetate catalyzed tertiary C-H insertion reaction of the diazomalonate (S)-5. The coupling of the acid (S)-4 with tryptamine produces the amide (S)-3, which is then transformed into the aldehyde 23 and hydroxy-lactam 24. Acid-mediated Pictet-Spengler
关键的手性非外消旋4,4-二取代的2-丁内酯羧酸(S)-4,可通过重氮丙二酸酯(S)-5的高效且立体有择的四乙酸二氢铑(II)催化的叔CH插入反应获得。酸(S)-4与色胺混合产生酰胺(S)-3,然后将其转化为醛23和羟基内酰胺24。酸介导的23-和24-Pictet-Spengler环化生成四环吲哚内酰胺(1S,12bS)-25a和(1S,12bR)-25b。经由内酰胺醇30a和30b,化合物25a和25b被转化为(-)-金丁胺(1a)和(+)-表金丁胺(1b)。