Bayer-Villiger reaction

Fischer and Holderich (1999) have shown that Bayer-Villiger reaction of cyclopentanone with aqueous 30 % H2O2, to give delta-valerolactone, is amenable to catalysis with cationic ion-exchange resin (CIER), Amberlyst-I5 without cataly.sts the conversion and the yield of the product are poor. Nafion on silica also works but was found to be poor compared to Amberlyst-15. Beta zeolite also works but was found to be inferior to Amberlyst-I5. 

Other mechanisms of ketone oxidation are also known and will be discussed in Chapter 8. Peracid, which is formed from aldehyde, oxidizes ketones with lactone formation (Bayer-Villiger reaction). 

This Bayer-Villiger reaction was supposed to proceed via the intermediate formation of the peroxyl adduct between peracid and the carbonyl group [25,43]. 

Enders and co-workers based their synthesis of (.R)-(-)-phoracantholide I (245) on their well-known SAMP methodology (Scheme 13) [205]. Thus, the SAMP derivative of cyclononanone (252) was deprotonated with LDA at 0 °C, and the resulting enolate was treated with CH3I at -100 °C to afford the a-methylated product 253 with >93% de. The latter was ozonized at -78 °C, and the resulting ketone (254) subjected to a Bayer-Villiger reaction to afford ( )-(-)-245 with 91% ee. 

The CD fragment 1s synthesized starting with resolved bicyclic acid 129. Sequential catalytic hydrogenation and reduction with sodium borohydride leads to the reduced hydroxy acid 1. The carboxylic acid function is then converted to the methyl ketone by treatment with methyl-lithium and the alcohol is converted to the mesylate. Elimination of the latter group with base leads to the conjugated olefin 133. Catalytic reduction followed by equilibration of the ketone in base leads to the saturated methyl ketone 134. Treatment of that intermediate with peracid leads to scission of the ketone by Bayer Villiger reaction to afford acetate 135. The t-butyl protecting... 

Irradiation of carbene complexes in CO atmosphere generates the ketene 305 and its [2+2] cycloaddition to alkene gives the cyclobutanone 306 [93], Total synthesis of (+)-cerulenin (310) has been carried out by the formation of cyclobutanone 309 by cycloaddition of 307 to the double bond of 308 as the key reaction without attacking the triple bond. Then cyclobutanone 309 was converted to (+)-cerulenin (310) via regioselective Bayer-Villiger reaction of 309, and side-chain elongation using n-methallylnickel bromide, epoxidation and hydrolysis [94],... 

The chemistry of A-[bis(trimethylsilyl)methyl]- 3-lactams provides interesting insight into the stability of these systems. The bis(trimethylsilyl)methyl group is not affected by conditions of the Bayer-Villiger reaction, by oxidation with lead tetraacetate or ester hydrolysis with lithium hydroxide.256 The acetoxy group could be displaced to form ether derivatives.256... 

One or both of the adducts may be active in various oxidations, and it is remarkable that the MT0/H202 system can effect both nucleophilic attack (Bayer-Villiger reaction) and electrophilic attack (olefin epoxidation). 

Once formed, alcohols esterify to some extent with the acids generated in an oxidation reaction. Except for lactones, esters do not appear to be generated directly in oxidation mechanisms [10, 37, 38]. The Bayer-Villiger reaction of intermediate peracids and ketones is sometimes proposed as a source of esters [39] but it appears to be too slow to be a significant source except in the case of cycloparaffins [10, 40]. The ester group and its immediate neighboring groups appear to be remarkably resistant to oxidation. 

When the 2-alkylcyclopentanones are subjected to the Bayer-Villiger reaction, the resultant lactones are found to have sweet, buttery, peach and coconut odours. These are useful in floral fragrances, but their major use is as butter flavour in margarines. 

Using urea-hydrogen peroxide with trifiuoroacetic anhydride cubane derivatives can undergo tris-Bayer Villiger reactions in good yield. This reaction can be accomplished with the use of MCPBA, however, the reaction was not successful when magnesium monoperoxyphthalate hexahydrate (MMPP) was used as the oxidation reagent. 

In a variation of the Bayer Villiger reaction, known as the Dakin reaction, the oxidation of aromatic aldehydes to phenols is accomplished via aryl formate... 

Ketones. The predominant synthetic use of peroxygens in ketone oxidation is the Bayer-Villiger reaction, which converts them to esters (cyclic ketones to lactones). The predominant product is determined by the relative stability of the carbocations of R and R in RCOR, and an approximate ranking is ... 

The first eiample of an Ireland-Qaisen rearrangement of an allyl lactone employed in natural product synthesis was that of Danishefsky and Tsuzuke in 1980 (Scheme 4.137) [132]. The allyl lactone possessed an exocyclic alkene, and hence resulted in a net 7-membered ring lactone to carbocycle conversion. A Bayer-Villiger reaction converted the pentenoic add to the 3° hydroxyl group of widdrol. 

FIGURE 3.20. Yeast-catalyzed Bayer-Villiger reaction. 

The phenolic function was generated with a Bayer-Villiger reaction (scheme 15). Peracetic acid or sodium perborate were used as oxidising agents in acetic acid at a temperature of 55-60°C. The subsequent transesterification with ethanol and HCl afforded the ester 17 whereas a hy olysis with aqueous hydrochloric acid gave the 4-(hydroxyphenoxy)propionic acid 18. The desired intermediate 19 was obtained either by transesterification of 17 or by a classical esterification of the acid 18 with only a 0.1 fold excess of oximeglycol in refluxing toluene. 

A good number of reviews, perspectives, highlights, focus, and account of research were published in the period under review. The topics covered included nitfation of aromatic compounds, oxidation processes, Pd catalysis, oxidative coupling, asymmetric transfer hydrogenation, Sm-Barbier reaction, use of hypervalent I2, and Bayer-Villiger reaction. 

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