Enantiospecific Total Synthesis of the Sarpagine Related Indole Alkaloids Talpinine and Talcarpine as Well as the Improved Total Synthesis of Alstonerine and Anhydromacrosalhine-methine via the Asymmetric Pictet−Spengler Reaction
作者:Peng Yu、Tao Wang、Jin Li、James M. Cook
DOI:10.1021/jo000126e
日期:2000.5.1
The enantiospecific total synthesis of talpinine 1 and talcarpine 2 has been accomplished from D-(+)-tryptophan in 13 steps (11 reaction vessels) in 10% and 9.5% overall yields, respectively. Moreover, this synthetic approach has been employed for the improved synthesis of alstonerine 3and anhydromacrosalhine-methine 4 in 12% and 14% overall yield, respectively. A convenient synthetic route for the enantiospecific
从13个步骤(11个反应容器)中,D-(+)-色氨酸的对映体总合成talpinine 1和talcarpine 2的总产率分别为10%和9.5%。此外,该合成方法已被用于分别以12%和14%的总产率改善合成的alstonerine 3和脱水Macrosalhine-methine 4。已开发了通过数百克级的不对称Pictet-Spengler反应对关键中间体(-)-N(a)-H,N(b)-苄基四环酮15a进行对映体,立体定向制备的便捷合成途径。非对映控制(> 30:1)的阴离子氧基-Cope重排和分子内重排以形成环E和N(b)-苄基/ N(b)-甲基转移反应也为关键步骤。