Baeyer-Villiger reaction side reactions

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°. ... 

A reaction sequence which complements the Baeyer-Villiger reaction has been described (equation 1) Regioselective silylenol ether formation allows for introduction of oxygen away from the more highly alkylated side of a ketone. 

The Baeyer Villiger reaction is an oxidation of ketones by peroxyacids that inserts an oxygen atom between the carbonyl group and the more substituted side of the ketone. The biological... 

Activation for the Michael reaction could be by C02Et group or enamine formation. Ring expansion of (16) to <14> is unambiguous as only the more substituted side chain migrates, as in the Baeyer-Villiger reaction (Chapter... 

Answer A ketone is being treated with a peroxy acid, so we expect a Baeyer-Villiger reaction to occur. We look closely at our starting ketone, and we see that it is unsynunetrical. So, we must predict where the oxygen atom will insert itself. We look at both sides, and we see that the left side is more substituted. The more substituted R group will migrate faster, and that is where the oxygen atom will be inserted. 

Peroxyacids are powerful oxidants and so side reactions are to be expected. Ketones are known to undergo Baeyer-Villiger " oxidation to the carboxylic acid ester on treatment with peroxyacids and so these by-products can be observed if oxime hydrolysis occurs during the oxidation. Paquette and co-workers " " observed such a by-product (61) during the oxidation of the dioxime (59) to the dinitro compound (60) with m-CPBA in hot acetonitrile. 

A new procedure (Scheme 3) using the Baeyer-Villiger oxidation of tetrahy-dro-4H-pyran-4-one (THP) was developed by Mathisen et al., which gave a better yield with no side-reactions, thereby facilitating the isolation of DXO [56]. 

Percarboxylic acids have been used widely in Baeyer-Villiger oxidation. Peracetic acid is one of the most commonly used peracids distilled peracetic acid is employed commercially by Solvay Interox for the production of e-caprolactone.246 The use of distilled peracetic acid is essential, as it contains no strong protic acids which can catalyse polymerization of the resulting lactone and cause other side reactions. Figure 3.53 illustrates the use of pre-formed peracetic acid for the Baeyer-Villiger oxidation of ketones.247,248... 

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