A Multicomponent Reaction of Acetals for the Preparation of Quinolines
作者:Xue-Lin Zhang、Qin-Pei Wu、Qing-Shan Zhang
DOI:10.3184/174751913x13814036942713
日期:2013.11
A straightforward, mild, one-pot method has been found for the preparation of quinolines via a multi-component reaction using acetals or cyclic acetals, aromatic amines and alkynes catalysed by Bi(OTf)3. It gives good yields under mild conditions. This approach has been successfully applied for the synthesis of a range of quinolines with a variety of functional groups.
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.