Hydrogenation of Aminoketones and Other Biologically Active Derivatives

Hydrogenation of Aminoketones and Other Biologically Active Derivatives 

Increasing interest has been shown in recent years for the synthesis of biologically active secondary alcohols by homogeneous catalytic stereoselective and enantioselective hydrogenation reactions. 

The first result in this field was the reduction of 2-(6-carbomethoxy-hexyl)cyclopentane-l,3,4-trione with [Rh(COD)(ACMP)2] BF4 as catalyst to 2-(6-carbomethoxy-hexyl)-4-(R)-hydroxycyclopentane-l,3-dione, an intermediate of the Ei prostaglandine synthesis (12)  

Japanese authors reported on the synthesis of (R)(-)-pantolactone (a precursor of pantothenic acid, which is an important constituent of coenzyme A) by hydrogenation of a-keto-/8,j8-dimethyl-y-butyrolactone with rhodium catalysts containing different chiral pyrrolidinediphosphines 

They found that the enantioselectivity of the reaction is highly influenced by the steric bulkiness of the substituents in the phosphine, while electronic factors play only a minor role. Working with the Rh-BPPM catalytic system R = tBuO), 86.7% optical yield was achieved under optimum reaction conditions, enabling the preparation of pure D(—)-pantoyl lactone in a single recrystallization step. 

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