Prepn. of 3-(2-chloro-phenyl)-2-(4-fluoro-phenyl)-propenal - by oxidising 2-(4-fluoro-phenyl)-ethanol in presence of 2-chloro-benzaldehyde and noble metal catalyst

摘要

The prepn. of 3-(2-chlorophenyl)-2-(4-fluorophenyl)-propenal of formula (I) comprises oxidising 2-(4-fluorophenyl)-ethanol of formula (II) in the presence of 2-chlorobenzaldehyde of formula (III) and in the presence of a noble metal catalyst. The 4-fluorophenyl acetaldehyde (IV) formed is aldol condensed in situ with the (III). USE/ADVANTAGE - (I) is an intermediate e.g. in the prepn. of triazole fungicides. The process generates (IV) and reacts it in situ with (III), thus avoiding the need to use (IV) itself, which is a very unstable cpd., the prepn. of which is very expensive.