ChemInform Abstract: Preparative Scale Stereoselective Synthesis of Methyl 4‐Methyl‐Z‐2,4‐pentadienoate.

Abstract

The stereoisomeric 4‐methyl‐2,4‐pentadienoates (IV) and (V) are prepared by three different methods: Bromination of mesityl oxide (I) to give the tribromide (II) and subsequent sodium methoxide (III) induced Favorskii rearrangement yield the Z‐isomer (IV) as the main product, whereas direct treatment of the bromide with triethylamine in methanol (VII) predominantly produces the E‐isomer (V).