作者:Douglas M. Mans、William H. Pearson
DOI:10.1021/ol048777a
日期:2004.9.1
The total synthesis of (+)-cocaine is described. An extension of the recently reported proline catalyzed intramolecular enol-exo-aldol reaction to a meso-dialdehyde provided the tropane ring skeleton directly with good enantiomeric excess. The meso-dialdehyde was prepared using a 2-azaallyllithium [3 + 2] cycloaddition to generate a cis-2,5-disubstituted pyrrolidine. Overall, the synthesis proceeded
[反应:见正文]描述了(+)-可卡因的总合成。最近报道的脯氨酸催化的分子内烯醇-exo-醛醇缩合反应向中二醛的延伸直接为托烷环骨架提供了良好的对映体过量。使用2-氮杂烯丙基锂[3 + 2]环加成制备顺式2,5-二取代的吡咯烷,制备了内消旋二醛。总体而言,从可商购的3-苄氧基-1-丙醇开始,在14个线性步骤中,合成以6.5%的收率和86%的ee进行。