Enantioselective preparation of C-ring fragment of cotylenin A via catalytic asymmetric intramolecular cyclopropanation of α-diazo β-keto ester
作者:Kotaro Nagatani、Yunosuke Hoshino、Haruka Tezuka、Masahisa Nakada
DOI:10.1016/j.tetlet.2017.01.076
日期:2017.3
A synthetic pathway to the C-ring fragment of cotylenin A which emerged from our retrosynthetic analysis of cotylenin A is described. The catalytic asymmetric intramolecular cyclopropanation (CAIMCP) of the α-diazo-β-keto ester bearing 2,4,6-trimethylphenyl group as the ester part has been found to afford the crystalline product with high ee, which allowed to establish the approach to the C-ring fragment
描述了从我们对辅肾素A的逆向合成分析中发现的一种对辅肾素A C环片段的合成途径。已发现带有2,4,6-三甲基苯基作为酯部分的α-重氮-β-酮酯的催化不对称分子内环丙烷化(CAIMCP)可以提供具有高ee值的结晶产物,从而为建立低ee的方法奠定了基础。需要十锅操作的C环片段。所开发的方法将有利于C环片段的大规模合成,从而可以合成辅肾素A.