Synthesis of <i>C</i><sub>2</sub>-Symmetric Bisamidines: A New Type of Chiral Metal-Free Lewis Acid Analogue Interacting with Carbonyl Groups
作者:Deniz Akalay、Gerd Dürner、Jan W. Bats、Michael Bolte、Michael W. Göbel
DOI:10.1021/jo070534j
日期:2007.7.1
compound adopts a planar conformation with an almost convergent orientation of two N−H groups. Ketones, aldehydes, and nitro compounds are assumed to bind to this strongly polar cleft via hydrogen bonds, resulting in a Lewis-acid-like activation of the carbonyl groups. A broad scope of reactions (Diels−Alder, hetero-Diels−Alder, Friedel−Crafts) can be catalyzed. The observed accelerations surpass the rate