Mercury acetate allylic oxidation

That mercury(II) acetate allylic oxidation can be a useful reaction in the case of complex and sensitive substrates is demonstrated by the oxidation of avermectin A2a (38). The reaction, carried out in anhydrous toluene at 100 C for 40 min, was remarkably selective, allylic oxidation occurring exclusively at the 3,4-double bond with rearrangement to give (39) in up to 73% yield (equation 17). 

Alkyl groups attached to aromatic rings are oxidized more readily than the ring in alkaline media. Complete oxidation to benzoic adds usually occurs with nonspecific oxidants such as KMn04, but activated tertiary carbon atoms can be oxidized to the corresponding alcohols (R. Stewart, 1965 D. Arndt, 1975). With mercury(II) acetate, allylic and benzylic oxidations are also possible. It is most widely used in the mild dehydrogenation of tertiary amines to give, enamines or heteroarenes (M. Shamma, 1970 H. Arzoumanian, 1971 A. Friedrich, 1975). 

On the basis of this and other evidence allylic mercuty(II) acetates are believed to be the reaction intermediates in all allylic oxidations with mercury(II) acetate. The isolation of the less stable secondary... 

Overall, many transition metal complexes have been investigated. Among those not mentioned above which may carry out catalytic allylic oxidation to give enones under certain drcumstances are Co(PPh3)Cl/02, Mn(TPP)Cl/02, [Fe(PPh3)]20AJV, Ni(phthalocyanine)/02 and an unusual mercury(II) acetate example in which the enone is formed rather than the expected acetate. 

Other transition metal salts mediate in similar oxidations. For example, mercury(II) acetate, a milder reagent than LTA, effects a-acetoxylation through a comparable mechanism. However the corresponding yields for these processes are poor. 3,3-Dimethylcyclohexanone, for example, is oxidized to the a-acetoxy derivative in only 14% yield.The, 7-unsaturated ketone, isopugelone, exhibits no oxidation at the a- or a -positions, but affords a product derived from isomerization of the alkene and allylic oxidation. Not surprisingly therefore the reagent has found little synthetic application for this transformation. 

While allylic oxidation products may arise by elimination of a metal hydride from an intermediate adduct or metal-alkene complex, allylmercury species (34) are thought to be intermediates in the case of mercury(II) acetate. A number of pathways have beien suggested, for example involving radical and carbenium ion intermediates, and addition-elimination and rearrangement inocesses. ... 

In contrast to lead tetraacetate, simple addition to the double bond does not occur as a side re-action. While allylic rearrangement is common and mixtures of products are frequently obtained, the reaction often proceeds in very high yield and is simple to carry out the alkene is simply heated in an appropriate solvent with mercury(II) acetate until reaction is complete. Mercury(II) acetate has also been us for dehydrogenation, particularly in the steroid field. One interesting example incorporating simultaneous dehydrogenation and allylic oxidative rearrangement is seen in the reaction of abietic acid (37 equation 16). ... 

AMINOETHYLETHANDIAMINE (111-40-0) Combustible liquid (flash point 208°F/ 98°C oc). An organic base. Ignites spontaneously with cellulose nitrate, and possibly other nitrogen compounds. Silver, cobalt, or chromium compounds may cause explosions. Contact with nitromethane forms a heat-, friction-, and shock-sensitive explosive. Incompatible with acids, acrylates, aldehydes, alcohols, alkylene oxides, caprolactam solution, cresols, organic anhydrides, substituted allyls, epichlorohydrin, glycols, halogenated compounds, isocyanates, ketones, mercury, phenols, strong oxidizers, vinyl acetate. Attacks aluminum, copper, cobalt, lead, tin, zinc, and their alloys. 

The cyclized analog of meralluride is prepared by a similar synthesis. Thus, condensation of camphoric acid (42) (obtained by oxidation of camphor) with ammonia gives the bicyclic succinimide (44). Reaction with allyl isocyanate followed by ring opening and then reaction with mercuric acetate affords the mercury derivative (45) as the acetate rather than the hydroxide as above. Reaction with sodium chloride converts that acetate to the halide (46). Displacement on mercury with the disodium salt of thioglycollic acid affords the diuretic mercaptomerine (47). ... 

Winstein showed that the solvolysis of crotylmercury(II) acetate under kinetically controlled conditions gives >99.5% of a-methylallyl acetate (equation 13). Subsequent work indicate that both the solvolysis of ciimamylmercury( acetate and this mercury(II) acetate oxidation of allylbenzene give ca. 60% cinnamyl acetate (35) a 40% a-phenylallyl acetate (36 equation 14). An equilibrium exists between (35) and (36) favoring the primary ester which constitutes >99.5% of the equilibrium mixture at 75 C. Oxidation of a range of both 1- and 2-alkenes under kinetically controlled conditions exclusively gave the secondary allylic esters. 

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