This invention relates to alkylamino alkylene derivatives of certain 2H-1-benzopyrans, to the intermediates are processes useful for their preparation, to their free-radical scavenger and cellular protective properties and to their end-use application as therapeutic agents.
Aromatic Cations from Oxidative Carbon–Hydrogen Bond Cleavage in Bimolecular Carbon–Carbon Bond Forming Reactions
作者:Dane J. Clausen、Paul E. Floreancig
DOI:10.1021/jo301185h
日期:2012.8.3
with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to form persistent aromatic oxocarbenium ions through oxidative carbon–hydrogen cleavage. This process is tolerant of electron-donating and electron-withdrawing groups on the benzene ring and additional substitution on the pyran ring. A variety of nucleophiles can be added to these cations to generate a diverse set of structures.
Bimolecular coupling reactions through oxidatively generated aromatic cations: scope and stereocontrol
作者:Yubo Cui、Louis A. Villafane、Dane J. Clausen、Paul E. Floreancig
DOI:10.1016/j.tet.2013.05.011
日期:2013.9
Chromenes, isochromenes, and benzoxathioles react with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone to form stable aromatic cations that react with a range of nucleophiles. These oxidative fragment coupling reactions provide rapid access to structurally diverse heterocycles. Conducting the reactions in the presence of a chiral Bronsted acid results in the formation of an asymmetric ion pair that can provide enantiomerically enriched products in a rare example of a stereoselective process resulting from the generation of a chiral electrophile through oxidative carbon hydrogen bond cleavage. (C) 2013 Elsevier Ltd. All rights reserved.