Diastereoselective Synthesis of the Pectenotoxin 2 Non-Anomeric AB Spiroacetal
摘要:
The reductive cyclization reaction of a cyanoacetal has been used to prepare the pectenotoxin 2 (PTX-2) AB spiroacetal with high diastereoselectively for the first time. The strategy is convergent and makes use of the axial-selective reductive lithiation of 2-cyano tetrahydropyran rings to introduce the spiroacetal center with the desired non-anomeric selectivity.
Diastereoselective Synthesis of the Pectenotoxin 2 Non-Anomeric AB Spiroacetal
摘要:
The reductive cyclization reaction of a cyanoacetal has been used to prepare the pectenotoxin 2 (PTX-2) AB spiroacetal with high diastereoselectively for the first time. The strategy is convergent and makes use of the axial-selective reductive lithiation of 2-cyano tetrahydropyran rings to introduce the spiroacetal center with the desired non-anomeric selectivity.
A Spirodiepoxide-Based Strategy to the A−B Ring System of Pectenotoxin 4
作者:Stephen D. Lotesta、Yongquan Hou、Lawrence J. Williams
DOI:10.1021/ol063087n
日期:2007.3.1
A synthesis of a pectenotoxin 4 C1-C15 segment is reported. Suitable C1-C7 and C8-C15 segments were prepared, coupled, converted to I and the C3-hydroxy variant, and then cyclized. Key findings include the stereoselective conversion of the allene to the corresponding spirodiepoxide, oxidative cleavage of the p-methoxybenzyl ether, and cyclization of the spirodiepoxide to spiroketal II.