Chemoselective Transfer Hydrogenation of Flavoring Unsaturated Carbonyl Compounds over Zr and Hf-based Metal-Organic Frameworks

摘要

The chemoselective hydrogenation of a carbonyl group in multiunsaturated aldehydes and ketones is a difficult task because hydrogenation of C=C bonds is favored thermody-namically over C=O bonds.Allylic alcohols are mostly used in the fine chemical industry for the production of pharmaceuticals,flavors,perfumes,and cosmetics.Many unsaturated carbonyls,which possess aroma and flavoring properties,can be produced using extraction from plant sources.However,the supply and the quality of traditional natural-flavor and fragrance chemicals are limited.Currently,around 90% of newly introduced fragrance ingredients are synthetic aroma chemicals.Benzaldehyde,cinnamaldehyde,citral,and carvone are widely used as reference unsaturated aldehydes.Cinnarizine,the cardiovascular drug,is derived from cinnamyl alcohol,whereas geraniol and nerol(derived from citral)are useful for the production of perfumes,food flavors,and insecticides.Vanillin is the most widely used flavor compound in the world and lignin,a major component of lignocellulosic bio-mass,could be utilized for the production of vanillin.