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
ASYMMETRIC REDUCTION OF ACETOPHENONE WITH CHIRAL REAGENTS FROM LITHIUM TETRAHYDROALUMINATE AND CHIRAL 1,2-DIOL OR DIAMINE AS STUDIED BY ALUMINUM-27 NUCLEAR MAGNETIC RESONANCE
作者:Junzo Yamashita、Shigemi Tomiyama、Harukichi Hashimoto、Keiichi Kitahara、Hisao Sato
DOI:10.1246/cl.1984.749
日期:1984.5.5
Asymmetricreduction of acetophenone with chiralreagentsfromlithium tetrahydroaluminate and (1S,2S)-1,2-diphenylethanediol or (1S,2S)-N,N′-diethyl-1,2-diphenylethanediamine in the presence or absence of added ethanol is studied by aluminum-27 NMR spectroscopy.