Villiger rearrangement

Baeyer-Villiger rearrangement and hydroxylation of acetophenone catalyzed by TS-I/H2O2 system... 

Oxidation of Ketones to Esters (Baeyer-Villiger rearrangement)... 

These relations are called Baeyer-Villiger rearrangement and in such reactions peroxytrifluoroacetic acid is used as an oxidising agent. 

Ab initio and semiempirical studies on the transition structure of the Baeyer-Villiger rearrangement of acetone with performic acid have been undertaken,510 and a theoretical investigation has been made511 of the mechanism of the Baeyer-Villiger reaction in non-polar solvents. The effect of fluoromethyl groups on the Baeyer-... 

RB3LYP calculations indicate that the s-cis conformer of peroxy acids is more stable than the s-trans conformer. Calculations on the reaction of prop-2-enol with some peroxy acids showed that trans-transition states collapse to the epoxide via a 1,2-shift, whereas a 1,4-shift is operable for cis-transition states.195 Quantum mechanical calculations have been performed on the migration step of the Baeyer-Villiger rearrangements of some substituted acetophenones with m-chloroperbenzoic acid (m-CPBA). The energy barriers, charge distributions and frontier molecular orbitals, determined for the aryl migration step, have been used to explain the effects of substituents on the reactivity of the ketones.196... 

Enol ethers of 1,2- and 1,3-diketones afford on ozonolysis products that are not in full agreement with the Criegee mechanism, because in some cases products of the Baeyer-Villiger rearrangement are formed. The main product in the ozonolysis of the enol ether 180 is a mixture of spiranic stereoisomers 181 involving a lactone and a 1,2,4-trioxolane ring (Scheme 62) <2004HCA2025>. 

So when the hydroxyketone 49 was needed for a pheromone synthesis, it was made by nucleophilic displacement on the lactone 50 by an organo-lithium compound. This lactone is of the right kind (cf. 45) to be made by a Baeyer-Villiger rearrangement from the cyclohexanone 51 and this can be made by total reduction of the phenol 52 (chapter 36). 

The reason for this becomes plain when you see that the new 1,6-diCO relationship does allow a very interesting reconnection. Adjustment of the oxidation state allows a reconnection to a lactone 61 that should be the product of a Baeyer-Villiger rearrangement on the ketone 62. 

The hydrogenation of 63 occurred quantitatively and with high stereoselectivity (25 1 in favour of 62). The regioselectivity was similarly good in the Baeyer-Villiger rearrangement (12 1) in favour of 61 over the isomeric lactone. Attempts to convert the lactone directly to 60 X = z-Bu gave only low yields. 

Scheme 4 Oxidation followed by Baeyer-Villiger rearrangement and transesterification of nitrated cardanol oil [86]...

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