Synthesis of 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazoles via the cyclopropyliminium rearrangement of substituted 2-cyclopropylbenzimidazoles
作者:Rinat F. Salikov、Dmitry N. Platonov、Aleksandr E. Frumkin、Dmitry L. Lipilin、Yury V. Tomilov
DOI:10.1016/j.tet.2013.02.021
日期:2013.4
2-Cyclopropylbenzimidazole derivatives with various substituents in the small ring undergo cyclopropyliminium rearrangement into 2,3-dihydropyrrolobenzimidazoles substituted at positions 1, 2 or 3. The substrates containing a functional group in position 1 of the cyclopropane ring form products substituted at position 3. Substituents at position 2 in most cases lead to the formation of a mixture of isomers. The reaction can be directed to yield one of the isomers predominantly by varying the solvent polarity. (C) 2013 Elsevier Ltd. All rights reserved.
Rhodium catalyzed enantioselective cyclization of substituted imidazoles via C–H bond activation
作者:Andy S. Tsai、Rebecca M. Wilson、Hitoshi Harada、Robert G. Bergman、Jonathan A. Ellman
DOI:10.1039/b902878a
日期:——
The enantioselective intramolecular alkylation of substituted imidazoles with enantiomeric excesses up to 98% has been accomplished by rhodium catalyzed C-Hbond functionalization with (S,S',R,R')TangPhos as the chiral ligand.