Total Synthesis of (+)-Alexine by Utilizing a Highly Stereoselective [3+2] Annulation Reaction of anN-Tosyl-α-Amino Aldehyde and a 1,3-Bis(silyl)propene
作者:Martina Dressel、Per Restorp、Peter Somfai
DOI:10.1002/chem.200701776
日期:2008.3.27
A novel route towards the polyhydroxylated pyrrolizidine alkaloid (+)-alexine has been developed. A key step in this synthesis is a highly stereoselective [3+2] annulation reaction of N-Ts-alpha-amino aldehyde 7 a (Ts=tosyl) and 1,3-bis(silyl)propene 8 a for the construction of the polyhydroxylated pyrrolidine subunit of the target molecule. Previous synthetic strategies rely on carbohydrates that
已开发出一种新的多羟基吡咯烷核生物碱(+)-阿雷西汀途径。该合成过程中的关键步骤是N-Ts-α-氨基醛7a(Ts =甲苯磺酰基)和1,3-双(甲硅烷基)丙烯8a的高度立体选择性[3 + 2]环化反应,靶分子的多羟基吡咯烷亚基。先前的合成策略依赖于碳水化合物,该碳水化合物需要几种保护基团的操作,从而使步骤的总数相对较高。[3 + 2]环空策略与基于碳水化合物的合成方法相比具有优势,并且构成了多羟基生物碱的高效入口。