Enamines oxidative cleavage

Strategies that lead to the formation of isoxazoles during cleavage from an insoluble support include the oxidative cleavage of /V-(4-alkoxybenzyl)isoxazolidincs with DDQ to yield isoxazolines (Entry 14, Table 15.16), the nucleophilic cleavage of 2-acyl enamines with hydroxylamine (Entry 15, Table 15.16), and the acidolysis of 2-cyano-phenols etherified with an oxime resin (Entry 17, Table 15.16). The required oxime ethers for the latter synthesis were prepared by reaction of the corresponding 2-fluorobenzonitriles with Kaiser oxime resin [203],... 

Copper complexes are particularly effective catalysts for the oxidative cleavage of enamines (equation 284)613-615 and 3-substituted indoles (equation 285)6 6,617 under extremely mild conditions ( 0°C). 

Chlorides and bromides of both oxidation states of copper, as well as cuprous cyanide, are active in promoting the oxidative cleavage of the enamine double bond (Scheme 21). 

Oxidative cleavage of an enamine double bond by Ru04 (prepared from Ru02 and NalOJ was first accomplished successfully by Desai and coworkers8 6 in the steroids series (Scheme 63). 

An interesting application to the synthesis of a-diketones, a-ketoesters and a-ketoa-mides, starting from ketones, esters and amides, was achieved by Wasserman and Ives . The method involves conversion of the starting carbonyl compound to the corresponding enamino carbonyl compound, followed by oxidative cleavage of the enamine double bond by singlet oxygen (Scheme 7). 

A similar reactivity was observed for piperidino enamines of linear ketones which gave a-amino ketones, derived by rearrangement of the epoxide intermediates, and products of carbon-carbon double-bond oxidative cleavage. ... 

Amino nitriles are useful for conjugate addition Acyl anion equivalents of the ester d1 synthon - C02R Methods Based on Vinyl (Enol) Ethers and Enamines Lithium derivatives of cyclic vinyl ethers The synthesis of pederin and related anti-tumour agents Lithium derivatives ofallenyl ethers Oxidative Cleavage of Allenes... 

A catalyst prepared by encapsulation of CUCI2 in zeolite X is useful for oxidative cleavage of enamines to afford amides. - ... 

Carboxylic acid amides and ketones from enamines by oxidative cleavage... 

The efficient removal of water formed during the reaction seems to be important as the enantiomeric ratio improved considerably upon using 5-A molecular sieves furthermore, oxygen-free conditions are required as substantial acetophenone and p-formylanisidine formation was observed in the presence of oxygen, presumably via an oxidative cleavage of the hydratopicaldehyde enamine intermediate. 

From the oxidation of enamines with aromatic nitro compounds a-keto-enamines were obtained in modest yields (70J). Photooxygenation led to cleavage of the enamine double bond (706,707). 

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