PROCESS FOR PREPARING 3 SUBSTITUTED 2 ALKENALS IN PARTICULAR PRENAL

摘要

11421122124861011211257571231249The present invention to a process for preparing 2 alkenals of the formula (I) in which R is selected from hydrogen and C C alkyl; and R is selected from hydrogen C C alkyl C C alkenyl C C cycloalkyl and C C aryl wherein C C alkyl and C C alkenyl may be substituted with C C cycloalkyl or C C cylcoalkenyl; comprising dehydrogenating an alkenol of the formula (II) an alkenol of the formula (III) or a mixture thereof wherein R and R are each as defined above wherein the alkenol II the alkenol III or a mixture thereof is brought into contact with a catalytic system comprising at least one ligand and a metal compound selected from ruthenium(II) compounds and iridium(I) compounds and wherein the hydrogen formed during the dehydrogenation is removed from the reaction mixture by: i) reaction with a reoxidant selected from C C alkanones C C cycoalkanones benzaldehyde and mixtures thereof; and/or ii) purely physical means.