Bayer-Villiger

Jones KH, RT Smith, PW Trudgill (1993) Diketocamphane enantiomer-specific Bayer-Villiger monooxygenases from camphor-grown Pseudomonas putida ATCC 17453. J Gen Microbiol 139 797-805. 

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. 

Oxidation of diphenyl or di-tert. butyl cyclopropenone with wi-chloro peroxy-benzoic acid207 proceeds via intermediates corresponding to a Bayer-Villiger-type mechanism 277/278) to unrearranged products (1,2-diketones) or rearranged products (ketones) depending on the reaction conditions. 

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]. 

Finally, we mention here recent progress made in the Bayer-Villiger oxidation. Zeolite Sn-Beta (1.6 wt.% Sn) was found to be an excellent catalyst [25], Thus, the monoterpene dihydrocarvone gives - with Sn-Beta and H202 - exclusively the lactone (Scheme 5.7), whereas m-chloroperbenzoic acid and Ti-Beta/H202 give the epoxide as the main product. 

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. 

In the past few years, new approaches for the enantioselective synthesis of / -benzyl-y-butyrolactones appeared in the literature. Some of these approaches involve the asymmetric hydrogenation of 2-benzyl-2-butenediols (j [34]), the radical mediated rearrangement of chiral cyclopropanes (r [35]), the transition metal catalyzed asymmetric Bayer-Villiger oxidation of cyclobutanones n [36]), or the enzymatic resolution of racemic succinates (g [37]). 

Bamiphylline, 426 Bamipine, 51 Barbital, 267, 268 Barbiturates, listing, 268, 269 Baroreceptors, 54 Bayer-Villiger lactone synthesis, 28, 31... 

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... 

The key step in the biosynthesis of brassinosteroids is the conversion of castasterone to brassinolide. This reaction is a lactonization of the steroidal B-ring or a Bayer-Villiger-oxidation. Tomato cell suspension cultures have been extensively studied in respect to the metabolism of 24-< / i-castasterone and 24-ep/-brassinolide [21, 22, 32, 33]. A microsomal fraction of tomato cell cultures, induced by 24-epi-castasterone, was able to convert this substrate into 24-epi-brassinolide (Fig. (11)). The specific enzyme activity was determined to be 230 fkat/mg protein with NADPH serving as the only accepted electrondonor [24],... 

The chemical properties of cyclic ketones also vary with ring size. Lower members (addition reactions, than corresponding acyclic ketones. The Cg—C12 ketones are unreactive, reflecting the strain and high enol content of medium-sized ring systems. Lactones are prepared from cyclic ketones by the Bayer-Villiger oxidation reaction with peracids. S-Caprolactone is manufactured from cyclohexane by this process ... 

The two oxidoreductase systems most frequendy used for preparation of chiral synthons include bakers yeast and horse liver alcohol dehydrogenase (HLAD). The use of baker s yeast has been recendy reviewed in great detail (6,163) and therefore will not be covered here. The emphasis here is on dehydrogenase-catalyzed oxidation and reduction of alcohols, ketones, and keto acid, oxidations at unsaturated carbon, and Bayer-Villiger oxidations. 

When the reaction is carried out at pH 7-8, however, ketone 4 is consumed rapidly because of the undesired Bayer-Villiger (B.V.) reaction of the intermediary hydroxy peroxysulfonate, which competes with the desired dioxirane formation (Scheme 6B.7). The suppression of the undesired B. V. reaction is indispensable for performing the desired epoxidation in a catalytic manner. Shi et al. have found that alkaline reaction conditions accelerate the conversion of the hydroxy peroxysulfonate to dioxirane and the reaction can be carried out with a catalytic amount (0.3 equiv.) of chiral ketone (Fig. 6B.3) [11], Alkaline conditions also bring about enhance-... 

Bayer-Villiger oxidation of the Ferrier carbocyclization products 69 and 70, derived from D-glucose, gave the isomeric 5-deoxyhexofuranosiduronic... 

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... 

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