Synthesis of Urea Derivatives from CO₂ and Silylamines

Abstract

A series of thirty-three N,N'-diaryl, dialkyl, and alkyl-aryl ureas have been prepared in pyridine or toluene by reaction of silylamines with CO₂ . This protocol is shown to provide facile access to ¹³ C-labeled ureas, as well as chiral and macrocyclic ureas. These reactions proceed through initial generation of the corresponding silylcarbamates, which subsequently react with silylamine under thermal conditions to afford the thermodynamically favored urea and disilyl ether.