Oxime O-allyl ethers

The reaction of isatoic anhydrides with the anions derived from active-methylene compounds has led to the isolation of a considerable number and variety of quinolones.There have been two reports of the preparation of cycloalkano-pyridines, e.g. (137), by thermolysis of cycloalkanone oxime O-allyl ethers, e.g. (135) an intermediate nitrone (136) is formed (Scheme 56). 

Eckersley, A. and N. A.J. Rogers. 1974. Thermolysis of oxime O-allyl ethers. Tetrahedron Lett 18 1661-1664. 

This series of rearrangements includes the dithia-Claisen rearrangement mentioned above (Section IV.E.l) as well as the palladium-catalyzed [3,3]-sigmatropic isomeriza-tions of allyl methyl N-aryldithiocarbonimidates 627 (refluxing dioxane, 20 h, 62-90%) (equation 275)376 and a Pd11-catalyzed tandem [2,3]-sigmatropic shift, followed by 1,3-dipolar cycloaddition which takes place at equilibrium between O-allyl ethers of oximes 628 and the corresponding N-allyl nitrones 629 (equation 276)377. 

Mikhaleva, A.I., O.V. Petrova, V.M. Bzhezovsky, and N.A. Kalinina. 1987. Unexpected transformation of O-allyl ether of cyclohexanone oxime in superbase media. B Acad Sci USSRChl 611- 61K... 

Intramolecular cycloaddition of fV-benzyl-substituted 3-O-allylhexose nitrones furnishes chiral oxepane derivatives. The regioselectivity of the cycloaddition depends on several factors such as (1) the structural nature of the nitrone, (2) substitution and stereochemistry at 3-C of the carbohydrate backbone, and (3) substitution at the terminus of the O-allyl moiety. A mixture of an oxepane and a pyran is formed in the intramolecular oxime olefin cycloaddition of a 3-O-allyl carbohydrate-derived oxime <2003T4623>. The highly stereoselective synthesis of oxepanes proceeds by intramolecular nitrone cycloaddition reactions on sugar-derived methallyl ethers <2003TA3899>. 

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