Polarographic reduction of aldehydes and ketones. Part XIV. Formation of trans- and cis-crotyl alcohol in the electroreduction of crotonaldehyde

Abstract

The protonated form of crotonaldehyde is reduced in a one-electron step to form a radical which dimerizes and gives a 1,2-diol. The unprotonated form at pH >8 is reduced to a radical anion, which is protonated and further reduced to crotyl alcohol. The sequence of reducibility of electroactive centres at the dropping mercury electrode for crotonaldehyde (CHO) is hence opposite to that for cinnamaldehyde (CC, CHO). The predominant reduction product of crotonaldehyde was trans-crotyl alcohol, but the fraction of the cis-crotyl alcohol was larger than the relative content of the cis-isomer in the crotonaldehyde used.