Baeyer ketone

Baeyer-Villiger Oxidation- oxidation of ketones to esters and lactones via oxygen insertion... 

The reaction of ketones with peroxy acids is both novel and synthetically useful An oxygen from the peroxy acid is inserted between the carbonyl group and one of the attached car bons of the ketone to give an ester Reactions of this type were first described by Adolf von Baeyer and Victor Vilhger m 1899 and are known as Baeyer—Villiger oxidations... 

Using Figure 17 15 as a guide write a mechanism for the ] Baeyer-Villiger oxidation of cyclohexyl methyl ketone by peroxybenzoic acid J... 

FIGURE 17 15 Mechanism of the Baeyer-Villiger oxida tion of a ketone... 

Section 17 16 The oxidation of ketones with peroxy acids is called the Baeyer-Vilhger oxidation and is a useful method for preparing esters... 

Compounds known as lactones which are cyclic esters are formed on Baeyer—Vilhger oxi dation of cyclic ketones Suggest a mechanism for the Baeyer—Vilhger oxidation shown... 

Baeyer-Villiger oxidation (Section 17 16) Oxidation of an aldehyde or more commonly a ketone with a peroxy acid The product of Baeyer-Vilhger oxidation of a ketone is an ester... 

A variety of esters can be prepared from the corresponding ketones usiag peracids ia a process usually referred to as the Baeyer-Villiger reaction (95) ie, cyclopentanone is converted to 5-valerolactone upon treatment of the ketone with peroxytrifluoroacetic acid ... 

BAEYER - DREWSON Indoxyl Synfhesis Conversion of o-nitrobenzaldehyde and ketones to indoxyls. 

BAEYER VILLIQER Ketone Oxidation Synthesis of esters or lactones trom ketones with retention of configuration... 

The choice of which reactions to include is not an easy one. First there are the well known "Name Reactions", that have appeared in various monographs or in the old Merck index. Some of these are so obvious mechanistically to the modern organic chemistry practitioner that we have in fact omitted them for instance esterification of alcohols with acid chlorides - the Schotten-Baumann procedure. Others are so important and so well entrenched by name, like the Baeyer-Villiger ketone oxidation, that it is impossible to ignore them. In general we have kept older name reactions that are not obvious at first glance. 

The Baeyer-Villiger oxidation of ketones to esters (or lactones) occurs by the following mechanism. 

The mechanism of this degradation has received considerable attention, and for some species the reaction is equivalent to a nonenzymatic Baeyer-Villager reaction, producing first the 17j8-acetate. This functionality can then be hydrolyzed and oxidized to the ketone and may undergo a second Baeyer-Villager reaction to produce a lactone ... 

While the oxidation of ketones by peracids (Baeyer-Villiger reaction) has been used in steroids mainly for ring cleavage, it has occasionally been applied to 20-ketopregnanes for conversion to 17-acetoxy- or hydroxyandros-tanes. The synthetic utility of this method is limited since reactive double bonds and other ketones are incompatible with the reagent. 

In the one application reported for the conversion of the 17jff-acetyl side-chain to the 17-ketone, the intermediate oxime was not isolated, but hydrolyzed in situ with acid in an overall yield of about 20 %. In the case of 17jff-acetyl-D-norandrostanes, which are particularly difficult to degrade to D-norandrostanes, the nitrite procedure proved the most convenient method. The yield is 25 %, nowhere near the much higher yield obtained by a Baeyer-Villiger reaction which, however, must be allowed to proceed for one month at 0°. ... 

In a typical Knof procedure, 3jS-hydroxyandrost-5-en-17-one acetate is epoxidized with perbenzoic acid (or m-chloroperbenzoic acid ) to a mixture of 5a,6a- and 5)5,6)5-epoxides (75) in 99 % yield. Subsequent oxidation with aqueous chromium trioxide in methyl ethyl ketone affords the 5a-hydroxy-6-ketone (76) in 89% yield. Baeyer-Villiger oxidation of the hydroxy ketone (76) with perbenzoic acid (or w-chloroperbenzoic acid ) gives keto acid (77) in 96% yield as a complex with benzoic acid. The benzoic acid can be removed by sublimation or, more conveniently, by treating the complex with benzoyl chloride and pyridine to give the easily isolated )5-lactone (70) in 40% yield. As described in section III-A, pyrolysis of j5-lactone (70) affords A -B-norsteroid (71). Knof used this reaction sequence to prepare 3)5-hydroxy-B-norandrost-5-en-17-one acetate, B-noran-... 

Baeyer-Villiger oxidation by trifluoraperoxyacetic acid converts a chlo-rofluoroalkyl ketone into an ester 7l ] (equation 63)... 

Compounds known as lactones, which are cyclic esters, are formed on Baeyer—Villiger oxidation of cyclic ketones. Suggest a mechanism for the Baeyer—Villiger oxidation shown. 

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