Zirconocene-catalyzed epoxy ester - ortho ester rearrangement: A new method for the protection of polyfunctionalized carboxylic acids and the asymmetric synthesis of ortho esters
作者:Peter Wipf、Wenjing Xu、Hongyong Kim、Hidenori Takahashi
DOI:10.1016/s0040-4020(97)01038-7
日期:1997.12
In situ prepared Cp2(Cl)Zr⊛ catalyzes the formation of ortho eśters from epoxy esters. Acid-sensitive α-amino and α-hydroxy acid derivatives are converted in high yield to 2,7,8-trioxabicyclo[3.2.1]octanes (ABO-esters) using this protocol. This strategy is complementary to the OBO-ester technology, and orthogonal methods for the deprotection of ABO- and OBO-esters have been developed. The syntheses
原位制备的Cp 2(Cl)Zr⊛催化环氧酯形成邻位酯。酸敏感的α-氨基和α-羟基酸衍生物可使用该方案高产率地转化为2,7,8-三氧杂双环[3.2.1]辛烷(ABO-酯)。该策略是OBO-酯技术的补充,并且已经开发了用于ABO-酯和OBO-酯脱保护的正交方法。蘑菇组分(S)-γ-羟基亮氨酸内酯和(S)-α-乙烯基甘氨酸的合成强调了ABO酯保护基策略的价值。使用手性环氧醇衍生物,已经实现了双环原酸酯的第一个方便且通用的不对称合成。