Asymmetric Desymmetrization Based on an Intramolecular Haloetherification: A Highly Effective and Recyclable Chiral Nonracemic Auxiliary, 2-exo-Methyl-3-endo-phenyl-5-norbornene-2-carboxaldehyde, formeso-1,3- andmeso-1,4-Diols
作者:Hiromichi Fujioka、Tetsuya Fujita、Naoyuki Kotoku、Yusuke Ohba、Yasushi Nagatomi、Atsushi Hiramatsu、Yasuyuki Kita
DOI:10.1002/chem.200400444
日期:2004.11.5
A new chiral auxiliary, a 3-endo-phenyl norbornene aldehyde derivative, which is a crystalline, very stable, and easily handled, was developed for the desymmetrization of meso-1,3- and meso-1,4-diols. The key step of the method, an intramolecular bromoetherification, proceeded in a highly diastereoselective manner. A four-step sequence, 1) acetalization, 2) intramolecular bromoetherification followed
开发了一种新的手性助剂3-内苯基降冰片烯醛衍生物,它是结晶的,非常稳定且易于处理的,可用于中消旋1,3-和1,4-消旋二醇。该方法的关键步骤是分子内溴醚化,它以高度非对映选择性的方式进行。分四个步骤进行:1)缩醛化; 2)分子内溴醚化,然后酸水解; 3)保护醇; 4)逆溴醚化,将内消旋二醇转化为旋光性衍生物。同时对3-内苯基降冰片烯醛衍生物进行了重整,可以重复使用。这是单一助剂的第一个化学实例,适用于内消旋1,3-和中消旋1,4-二醇的高度对映选择性脱对称。据我们所知,