A Facile and Efficient Method for the Formation of Unsymmetrical Ureas Using DABAL-Me3
作者:Byung-Hoon Jeong、Hee-Kwon Kim、David H. Thompson
DOI:10.1071/ch15675
日期:——
A practical synthetic method for the formation of unsymmetrical-substituted ureas is described. The synthesis of the unsymmetrical ureas was readily performed from 2,2,2-trichloroethyl carbamate compounds by treatment of amines with bis(trimethylaluminum)-1,4-diazabicyclo[2.2.2]octane (DABAL-Me3). Using this reaction protocol, various trisubstituted and tetrasubstituted ureas were synthesized in high
Medium-Ring Nitrogen Heterocycles through Migratory Ring Expansion of Metalated Ureas
作者:Jessica E. Hall、Johnathan V. Matlock、John W. Ward、Katharine V. Gray、Jonathan Clayden
DOI:10.1002/anie.201605714
日期:2016.9.5
benzo‐fused nitrogen heterocycles (indolines, tetrahydroquinolines, and their homologues) undergo migratory ring expansion through deprotonation of their benzylic urea derivatives with lithium diisopropylamide (LDA) in the presence of N,N′‐dimethylpropylideneurea (DMPU). The products of the reactions are benzodiazepines, benzodiazocines, and their homologues, with ring sizes of 8–12. The reactions tolerate a