Progress on Decarboxylation and Hydroxylation of Carboxylic Acids

Carboxylic acids are inexpensive, readily available, stable and functionally diverse molecules, and alcohols are used as important functional molecules in a variety of applications. Therefore, decarboxylative hydroxylation of carboxylic acid provides a direct and rapid route to important alcohol molecules from stabilized and easily obtainable carboxylic acid feedstocks through benign single carbon excision reductions, which is a very important and useful transformation in organic synthesis and nature. The research progress on decarboxylative hydroxylation reactions to obtain the corresponding primary, secondary and tertiary alcohols, mainly in terms of transition metal catalysis, photocatalysis, electrocatalysis and other types of catalysis, is highlighted with an emphasis on the possible mechanisms and applicable scope of these different reactions. Among them, transition metal catalysis emerged earlier and produced tertiary alcohols in higher yields, but with less universal substrates, whereas photocatalysis is a mild reaction with low environmental pollution and is suitable for the production of primary, secondary and tertiary alcohols.