Ein einfacher Zugang zu (<i>R</i>)-α-Hydroxycarbonsäuren und (<i>R</i>)- 1-Amino-2-alkoholen aus (<i>R</i>)-Cyanhydrinen
作者:Thomas Ziegler、Brigitte Hörsch、Franz Effenberger
DOI:10.1055/s-1990-26945
日期:——
A Convenient Route to (R)-α-Hydroxy Carboxylic Acids and (2R)-1-Amino-2-alkanols from (R)-Cyanohydrins (R)-Cyanohyrins, prepared in good to excellent yields with high optical purity by enzyme-catalyzed addition of hydrogen cyanide to aldehydes in organic solvents, are hydrolyzed with concentrated hydrochloric acid at ambient temperature, usually in very high yield, without any trace of racemization to give (R)-α-hydroxy carboxylic acids. Likewise, no racemization is observed by direct reduction of the (R)-cyanohydrins with lithium aluminum hydride to give (2R)-1-amino-2-alkanols.
一条便捷途径:由(R)-氰醇制备(R)-α-羟基羧酸和(2R)-1-氨基-2-烷醇
通过酶催化氢氰酸与醛在有机溶剂中加成反应制备的(R)-氰醇,具有良好的至极佳的产率和高光学纯度。这些(R)-氰醇在室温下用浓盐酸水解,通常以非常高的产率,且无任何消旋化痕迹,生成(R)-α-羟基羧酸。同样地,通过直接用氢化锂铝还原(R)-氰醇,也未观察到消旋化现象,从而得到(2R)-1-氨基-2-烷醇。