Baeyer-Villiger cleavage

Because it is often possible to control the stereochemical orientadon of substituents on a cyclic array, Baeyer-Villiger cleavages of substituted cyclic ketones have been used extensively in the stereocon-trolled syndieses of substituted carbon chains. An asymmetric syndiesis of L-daunosamine intermediate... 

Because it is often possible to control the stereochemical orientation of substituents on a cyclic array, Baeyer-Villiger cleavages of substituted cyclic ketones have been used extensively in the stereocon-trolled syntheses of substituted carbon chains. An asymmetric synthesis of L-daunosamine intermediate (30) from a noncarbohydrate precursor employed the cyclopentenol (28), prepared in optically pure form (95% ee) from 2-methylcyclopentadiene using asymmetric hydroboration (Scheme 8). Stereoselective epoxidation, conversion to Ae ketone and regioselective Baeyer-Villiger oxidation afforded lactone (29). 

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. 

Cleavage of methyl ketones with peracids (Baeyer-Villiger)... 

Tr.e cyclic amino acid (25) could be made from a,e-di-cromo acid (26) and this can be made from (27) by a-trominatlon and replacement of hydroxyl by Br. This 1, 6-difunctionalised compound (27) is simply the ring -pened form of lactone (28), the Baeyer-Villiger p T 226) cleavage product from cyclohexanone. 

It was postulated (169) that these amides are 8,8a-secobenzophenanthridine alkaloids produced by oxidative cleavage of ring B of the corresponding benzophenanthridines. The success of Baeyer-Villiger-type oxidations of the immonium bond of benzophenanthridine skeletons (168,171,172,175) indicates that this type of oxidation could be a real biological pathway. 

Baeyer-Villiger products 121 were thought to undergo ring cleavage to isocyanates 122, which upon cyclization form products 123. 

Renaud and co-workers used 78 for the synthesis of (-)-phaseolinic acid (6) and (-)-pertusarinic acid (8) (Scheme 12) [32, 33]. Radical addition of dimethyl phenylselenomalonate to 78 proceeded with rearrangement of the bicyclics to yield the seleno-acetal 79 [34]. After reductive deselenylation and Baeyer-Villiger oxidation treatment of 80 with BU4NI and BBr3 led to a simultaneous cleavage of the ether, the lactone, and the methyl ester func-... 

Polymer-supported persulfonic acid was prepared from potassium persulfate and the cation exchange resin P—SO3H in water. The authors reported various applications of this new oxidizing reagent such as epoxidation of olefins, Baeyer-Villiger reaction and cleavage of disulfide and Af-formylamino acids. 

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