A convergent approachtowardsnonsymmetrical 2,5-diester pyrroles is described. The buildingblocks can be easily assembled in less than four steps allowing for facile construction of diversity. The synthesis uses a rhodium-catalyzed NH insertion, followed by a one-pot deprotection-condensation to yield the desired pyrroles.
Metalation of α-diazocarbonyl compounds using Grignard reagents. A convenient synthesis of α-diazo-β-ketoesters and mixed esters of α-diazomalonate
作者:Erick Cuevas-Yañez、Joseph M. Muchowski、Raymundo Cruz-Almanza
DOI:10.1016/j.tetlet.2004.01.074
日期:2004.3
alpha-Diazocarbonyl compounds react with methylmagnesium bromide at -78 degreesC generating the corresponding alpha-diazo-alpha-bromornagnesio species, which can be intercepted by various electrophilic reagents. For example, with alkyl chloroformates alpha-diazo-beta-ketoesters or mixed esters of alpha-diazomalonate are obtained in good yields. (C) 2004 Elsevier Ltd. All rights reserved.