Tandem Aza-Wittig/Carbodiimide-Mediated Annulation Applicable to 1,2-Diaza-1,3-dienes for the One-Pot Synthesis of Fully Substituted 1,2-Diaminoimidazoles
摘要:
One-pot sequential aza-Michael, Staudinger, and aza-Wittig reactions on 1,2-diaza-1,2-dienes (DDs) can afford fully substituted 1,2-diaminoimidazoles. A plausible mechanism for the imidazole core formation involving an intramolecular ring closure of the carbodiimide-derived phosphazene intermediate is given. The reported strategy has sufficient flexibility to allow substituted 1,2-diaminoimidazoles with orthogonal nitrogen-protective groups to be generated from a variety of heterocumulene moieties linked to the DDs skeleton.
Synthesis of Functionalized Pyrroles via Catalyst- and Solvent-Free Sequential Three-Component Enamine−Azoene Annulation
作者:Orazio A. Attanasi、Gianfranco Favi、Fabio Mantellini、Giada Moscatelli、Stefania Santeusanio
DOI:10.1021/jo200287k
日期:2011.4.15
A new and efficient synthesis of polysubstituted pyrroles by a sequential one-pot three-componentreaction between primary aliphatic amines, active methylene compounds, and 1,2-diaza-1,3-dienes (DDs) is reported. The reactions were performed without catalyst and under solvent-free conditions with complete control of pathway selectivity. Notably, the ready availability of the starting materials and