Convenient and highly efficient chromatographic resolution of BINOL and of 6,6′-dibromo-BINOL via N(α)-Boc-tryptophan esters
作者:Bhavesh M. Panchal、Cathy Einhorn、Jacques Einhorn
DOI:10.1016/s0040-4039(02)02268-2
日期:2002.12
Racemic [1,1′]binaphthalenyl-2,2′-diol (BINOL, (±)-1) has been esterified with various commercially available N-protected-l-amino acids, giving the corresponding diastereomeric esters. Their TLC separation factors were highly dependent on the amino acid pattern. Diesters of (±)-1 and N(α)-Boc-tryptophan (3a) showed unusually large separation factors, which allowed their efficient separation by simple
外消旋的[1,1']萘基-2,2'-二醇(BINOL,(±)-1)已用各种市售的N-保护的-1-氨基酸酯化,得到相应的非对映体酯。它们的TLC分离因子高度依赖于氨基酸模式。(±)-1和N(α)-Boc-色氨酸(3a)的二酯显示出异常大的分离因子,可通过简单的柱色谱法对其进行有效分离。在非常温和的条件下除去色氨酸部分,以高总收率和100%ee提供每个对映异构体1。该方法也成功解决了外消旋6,6'-二溴-[1,1']二萘基-2,2'-二醇(6,6'-二溴-BINOL,(±)-2)。