Green Functional Group Transformations by Supported Ruthenium Hydroxide Catalysts

Abstract

This account summarizes our recent research on green functionalgroup transformations using easily prepared supported rutheniumhydroxide catalysts [Ru(OH) x /support,support = Al 2 O 3 , TiO 2 ,or Fe 3 O 4 ]. Various kinds of functionalgroup transformations, e.g. the oxidation (oxidative dehydrogenation)of alcohols and amines, hydrogen-transfer reactions, such as racemizationand reduction, and the hydration of nitriles, can be promoted bythe concerted activation of the substrates (including alcohols,amines, and nitriles) by the Lewis acid and Bronsted basesites on the Ru(OH) x /support catalyst. In addition,we have successfully developed three novel catalytic transformationswith the Ru(OH) x /support catalysts: (1) theoxygenation of primary amines to give amides, (2) the direct oxidativesynthesis of nitriles from primary alcohols and ammonia, and (3)the N-alkylation of ammonia (or its surrogates) with alcohols toproduce symmetrically substituted tertiary or secondary amines.The catalyses for these transformations are truly heterogeneous,and the catalysts retrieved after the transformations can be reusedwith retention of their high catalytic performance. 1 Introduction 2 Preparation and Characterization of Supported Ruthenium HydroxideCatalysts 3 Oxidation of Alcohols and Amines 4 Hydration of Nitriles 5 Oxygenation of Primary Amines To Give Amides 6 Direct Oxidative Synthesis of Nitriles from Primary Alcoholsand Ammonia 7 N-Alkylation of Ammonia with Alcohols To Give Tertiary orSecondary Amines 8 Conclusion