Process for preparing 2,3-unsaturated alcohols

A process for the preparation of unsaturated alcohols of the formula

• wherein
• R1 and R2 are each independently from one another selected from C1-C20-alkyl which is unsubstituted or substituted with 1 to 5 identical or different radicals R4, C2-C20-alkenyl which contains 1, 2, 3, 4 or 5 double bonds and is unsubstituted or substituted with 1 to 5 identical or different radicals R5;
• provided that R1 and R2 are different from each other;
• R3 is selected from hydrogen and C1-C4-alkyl;
• R4 is selected from hydroxyl, cyano, C3-C7-cycloalkyl and C1-C4-alkoxy,
• R5 is selected from hydroxyl, cyano, C1-C4-alkyl, C3-C7-cycloalkyl, C1-C4-alkoxy;
• which comprises subjecting unsaturated aldehydes of the formula
• wherein R1, R2 and R3 have the above defined meanings, to a hydrogenation in the presence of a catalyst and a tertiary amine;
• characterized in that the hydrogenation takes place in a reactor cascade.