Iron(III)-Catalyzed and Air-Mediated Tandem Reaction of Aldehydes, Alkynes and Amines: An Efficient Approach to Substituted Quinolines
作者:Ke Cao、Fu-Min Zhang、Yong-Qiang Tu、Xiao-Tao Zhuo、Chun-An Fan
DOI:10.1002/chem.200900875
日期:2009.6.22
Economic and practical advantages are offered by the iron(III)‐catalyzed and air‐mediated tandem coupling/hydroarylation/dehydrogenation of simple readily available aldehydes, alkynes, and amines for the synthesis of 2, 4‐disubstituted quinolines (see scheme).
Aromatic imines react with phenylacetylene or styrene in an acetonitrile solution of iron(III) chloride to give quinolines 3 or their tetrahydro derivatives 11 together with variable amounts of products 4 arising from the reduction of the imines. The initial step appears to be a one-electron oxidation to generate iron(II) and an imine radical cation. When the reactions are carried out in the presence of stoichiometric amounts of tetrachloro-p-benzoquinone (chloranil), only quinolines 3 are obtained.