1.7.5 Copper Catalyzed Reactions
1.7.5.1 Oxidation of Alcohols
Copper(I) complexes have been extensively explored for the oxidation of alcohols to aldehydes and ketones in the presence of molecular oxygen. Several studies have focused as functional model of galactose oxidase for the oxidation of primary alcohols to aldehydes. For example, copper(I)-complex with (2,2,6,6-tetramethylpiperidin-1yl)-oxyl (TEMPO) has been successfully found to catalyze the oxidation of primary and secondary alcohols to give aldehydes and ketones in fluorous biphase system (Scheme 13). The fluorous phase having the catalyst can be recycled without loss of activity.
 |
Scheme 13 |
1.7.6 Reactions with Other Catalysts
1.7.6.1 Osmium Catalyzed Reactions
The osmium-catalyzed oxidation of alcohols and dihydroxylation of alkenes has been explored with molecular oxygen as terminal oxidant. For example, K2OsO2(HO)4 in combination with DABCO has been found to catalyze the oxidation of cyclooctanol to cylooctanone in the presence of molecular oxygen (Scheme 14). This reaction condition has been demonstrated as effective system for the dihydroxylation of a-styrene to afford the corresponding 1,2-diol in high yield.
 |
Scheme 14 |
1.7.6.2 Gold Catalyzed Oxidation of Alcohols
Gold nanoparticles deposited on CeO2 nano crystals have been used as recyclable catalyst for the oxidation of alcohols to aldehydes and ketones in the presence of molecular oxygen (Scheme 15).
 |
Scheme 15 |