A novel and practical synthetic route is presented for the preparation of methyl-(E)-2-(3-(3-(2-(7-chloro-2-quinolinyl)ethenyl)phenyl)-3-oxopropyl)benzoate,the key intermediate of Montelukast,a leukotriene antagonist.The main diarylpropane framework was prepared via a polarity conversation reaction resulting in an acyl anion equivalent followed by a nucleophilic substitution reaction.The overall yield of this approach was 61％.This method is simple for operation and suitable for industrial production.