Bifunctional oxazoline-thiourea-based organocatalysts were synthesized and applied to the aza-Henryreactions between N-Boc aryl imines and nitromethane in high ee and chemical yields at room temperature.
合成了基于恶唑啉-硫脲的双功能有机催化剂,并将其应用于 N-Boc 芳基亚胺与硝基甲烷之间的 aza-Henry 反应,在室温下具有高 ee 和化学产率。
Chiral Proton Catalysis: A Catalytic Enantioselective Direct Aza-Henry Reaction
作者:Benjamin M. Nugent、Ryan A. Yoder、Jeffrey N. Johnston
DOI:10.1021/ja031906i
日期:2004.3.1
during an enantioselectivereaction, this work represents the first example of this phenomenon outside of a protein. A chiral, nonracemic BisAMidine (BAM) ligand was designed, synthesized, and complexed to the proton of a Brønsted acid. The resulting coordination compound catalyzed the production of enantioenriched product from the combination of a Schiff base and nitroalkane (the aza-Henryreaction). This
ammonium chlorides to provide the corresponding aza-Henry adducts in good yields and very high selectivities. It represents the first general enantioselectiveaza-Henry method for azomethines derived from enolizable aldehydes, giving rise to enantiomeric excesses above 94%. In addition, the reactions with nitroethane afforded high diastereo- and enantioselectivities (syn:anti up to 95:5; up to 98% ee for syn)