Payne’s reagent

In contrast, epoxidation with Payne s reagent results only in 4. The epoxide 3 has been used to prepare methyl 6a-fluoroshikimate (5) by treatment with HF in pyridine and removal of the acetonide group. 

Nitroxides. Payne s reagent is the most satisfactory oxidant for conversion of substituted piperidines to their nitroxides in a nonpolar solvent. The reaction is catalyzed by sodium tungstate. Yields are equally high with m-chloro-... 

Arene oxides. The reaction of this carbodiimide (supplier Aldrich) with hydrogen peroxide generates a peroxycarboximidic acid (1) (c/ Payne s reagent 6, 455-456). In combination with acetic acid, 1 converts phenanthrene into the 9,10-oxide (28% yield) and pyrene into the 4,5-oxide (27% yield). Some other carbodiimides can be used in this reaction. ... 

Oxidation of 3-allenic alcohols of the type (1) with Payne s reagent results in formation of 7-lactones (2) probably via an allenic oxide (a). ... 

EpoxidatUm. Bach and Knight recommend this reagent of Payne s for large-scale epoxidations, since it is inexpensive and safer to handle than peracids. An example cited is the epoxidation of c/s-cyclooctene (4.4 moles) (equation 1). 

There is an exception to the poor reactivity exhibited by hydrogen peroxide. When 158 was treated with 30% hydrogen peroxide, in the presence of benzonitrile and potassium hydrogen carbonate, epoxide 159 was formed in 86% yield, in what is known as the Payne epoxidatlon. l The reagents shown generate per-oxybenzimidic acid in situ. This transformation was taken from Smith s synthesis of (+)-calyculin A.250 Payne epoxidation is known to give a diastereofacial preference that is opposite to epoxidations with peroxy-acids. In this particular example, the epoxide 159 was a 3 1 (a P) mixture of isomers at the epoxy carbon. 

KHCOg, benzonitrile, methylenecyclohexane, and SO -HgOg added to methanol, stirred 18 hrs. with water-cooling below 30°, then warmed 4 hrs. at 45° - 1-oxa-spiro [5.2] octane. Y 73%.—The reagent is operative under mildly alkaline conditions. F. e. s. G.B. Payne, Tetrahedron 18, 763 (1962). 

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