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
Metal-assisted fragmentation of N-aryl- and -alkyl-N-trimethyl-silylaminosulfur chlorides and N-aryl- and -alkyl-aminosulfur chlorides in the presence of conjugated dienes: synthesis and reactivity of 2-substituted-3,6-dihydro-1,2-thiazines
作者:Martin R. Bryce、Antony Chesney、Graham N. McKelvey、Andrei S. Batsanov、Judith A. K. Howard、Martin Anderson
DOI:10.1039/p19960001825
日期:——
N-Alkyl- and -aryl-N-trimethylsilylaminosulfur chlorides 2 and N-aryl- and -alkyl-aminosulfur chlorides 8 fragment in the presence of silver ions and a conjugated diene to yield 2-substituted-3,6-dihydro-1,2-thiazines 6 as the major products, possibly via transient metal-coordinated thionitroso species. By judicious choice of the substituent on the nitrogen atom, the 1,2-thiazines 6 can be stabilised by an intramolecular non-bonded oxygen ⋯ sulfur or sulfur ⋯ sulfur interaction, e.g. structures 9 and 6j. Reactions of 1,2-thiazine derivatives 6g and 6i with butyllithium, followed by addition of methyl iodide, afforded the ring-opened products 21g and 21i, respectively. Reaction of transient pentacarbonyl-(tetrahydrofuran)chromium with compound 6b afforded the pentacarbonylchromium derivative 22 which was characterised by X-ray crystallography.
Alkylthionitroso and arylthionitroso compounds generated from N-trimethylsilyl-N-chlorothioalkylamine precursors
作者:Martin R. Bryce、Antony Chesney、Julie N. Heaton、Graham N. McKelvey、Martin Anderson
DOI:10.1016/s0040-4039(00)77083-3
日期:1994.7
A range of alkylthionitroso and arylthionitroso compounds have been generated by thermal fragmentation of N-trimethylsilyl-N-chlorothioalkyl(aryl)amine precursors, and intercepted by reaction with dimethylbutadiene to afford Diels-Alder and ene adducts.
7,8,9,10-Tetrahydro-6,6,9-trimethyldibenzo[b,d]pyran and 5,6,7,8,9,10-hexahydro-6,6,9-trimethylphenanthridine have been prepared by reaction of pulegone with lithium ortho-lithium phenolate and lithium ortho-lithium N-trimethylsilylaniline. The cyclization into the annellated systems could be performed under essentially non-acidic conditions.