Bifunktionelle Katalysatoren zur Synthese cyclischer Carbonate aus Oxiranen und Kohlendioxid

Preparation of Cyclic Carbonates from Oxiranes and Carbon Dioxide in the Presence of Bifunctional Catalysts Mixtures of metal halides and alkylammonium iodides catalyze the synthesis of cyclic carbonates 2 from oxiranes and carbon dioxide at room temperature and atmospheric pressure. The chemoselective reaction proceeds smoothly with mono‐substituted oxiranes while 1,2‐disubstituted substrates are inert. By the use of chiral oxiranes the reaction opens a simple access to chiral carbonates like ( R )‐ and ( S )‐4‐(chloromethyl)‐1,3‐dioxolan‐2‐one ( 2c ). Insertion of carbon dioxide into the CO bond occurs with retention of configuration and with optical yields of 73 – 98%.