Organosilicon synthesis of isocyanates: II. Synthesis of aliphatic, carbocyclic, and fatty-aromatic isocyanates
作者:A. V. Lebedev、A. B. Lebedeva、V. D. Sheludyakov、S. N. Ovcharuk、E. A. Kovaleva、O. L. Ustinova
DOI:10.1134/s1070363206030182
日期:2006.3
Silylation of a series of aliphatic, carbocyclic, and fatty-aromatic amines gave the corresponding silyl derivatives whose yield depended on the electronic and steric structure of the substrate and the nature of the silylating agent. The yield of isocyanates obtained by phosgenation of the silyl derivatives under mild conditions decreased in going from aliphatic amines to benzylamines and rose as the length of the alkyl chain in fatty-aromatic amines extended. The most convenient procedure for the synthesis of low-boiling alkyl isocyanates was found to be based on the transformation of amines or ammonium salts into silyl or silyl silyl-carabamates. followed by pyrolysis of the latter in the presence of trichloro(phenyl)silane.
Synthesis of Urea Derivatives from CO
<sub>2</sub>
and Silylamines
作者:Maotong Xu、Andrew R. Jupp、Maegan S. E. Ong、Katherine I. Burton、Saurabh S. Chitnis、Douglas W. Stephan
DOI:10.1002/anie.201900058
日期:2019.4.16
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 13C‐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
Zirconium Hydroaminoalkylation. An Alternative Disconnection for the Catalytic Synthesis of α-Arylated Primary Amines
作者:Ana Koperniku、Paul J. Foth、Glenn M. Sammis、Laurel L. Schafer
DOI:10.1021/jacs.9b10465
日期:2019.12.4
Primaryamine products have been prepared using zirconium catalyzed hydroaminoalkylation of alkenes with N-silylated benzylamine substrates. Catalysis using commercially available Zr(NMe2)4, affords an alternative disconnection to access α-arylated primaryamines upon aqueous work-up. Substrate dependent regio- and diastereoselectivity of the reaction is observed. Bulky substituents on the terminal