Isocyanates, Part 4. Convenient Phosgene-Free Method for the Synthesis and Derivatization of Enantiopure α-Isocyanato Carboxylic Acid Esters
作者:Hans-Joachim Knölker、Tobias Braxmeier
DOI:10.1055/s-1997-928
日期:1997.8
A novel phosgene-free procedure for the synthesis of α-isocyanato carboxylic acid esters starting from α-amino acid esters has been achieved. The isocyanates are obtained enantiomerically pure (>99% ee) by a DMAP-catalyzed isocyanation with di-tert-butyl dicarbonate, which proceeds in 10 min at room temperature. In situ derivatization of the isocyanates by reaction with amines and alcohols affords the corresponding enantiopure ureas and carbamates.
以δ-氨基酸酯为起点合成δ-异氰酸羧酸酯的不含光气的新方法已经实现。通过 DMAP 催化与二碳酸二叔丁酯的异氰酸酯化反应,可在室温下 10 分钟内获得对映体纯度大于 99% 的异氰酸酯。异氰酸酯通过与胺和醇反应进行原位衍生,可得到相应的对映体脲和氨基甲酸酯。