Several 7-norbomadienyl derivatives have been synthesized utilizing the reaction of norbornadiene and t-butyl perbenzoate. In addition, an

Ozonolysis of a series of cis and trans olefins indicates that the ozonide cis'.trans ratio produced in both normal ozonides and cross-ozonides is a function of both olefin stereochemistry and steric effects in the olefin. Isolation of an epoxide in which the olefin stereochemistry has been preserved has been observed in the case of one trans olefin. The mechanistic consequences of these results are discussed.It has now been amply demonstrated2-9 that olefins can give both cis and trans ozonides. Of greater significance to the mechanism of ozonolysis are a few observations which indicate that the ozonide cistrans ratio obtained can be a function of olefin stereochemistry. A different ozonide cis'.trans ratio is obtained from the stereoisomers of di-?-butylethylene,2 1,4-dibromo-2,3-dimethylbutene-2,3 methyl p-methoxycinnamate,6 and a number of simple alkenes.7-9Also of considerable importance to the study of the mechanism of ozonolysis are the reports by several groups5,8-10 that unsymmetrical olefins give, in addition to the expected unsymmetrical ozonide cis-trans pair, two symmetrical ozonide cis-trans pairs derived from the cleavage of the olefin unsaturation. We have recently shown that a combination of these two important pieces of information, that is, the formation of cross-ozonides and the observation of ozonide cis-trans pairs, can be used to provide results which raise serious questions about the general validity of the Criegee mechanism of ozonolysis.11 Specifically, it was shown that the ozonide cis'.trans ratios observed in cross-ozonides are also dependent upon olefin geometry.12 In these cases the intervention of an intramolecular stereoselective pathway, such as was considered to explain similar results in the normal ozonide cases,8-9 is not possible. These results have led us to propose a new path to ozonide formation in which the mol ozonide assumes the role of a true intermediate in an exchange reaction with aldehydes, and, thus, exerts an influence on the ozonide cis'.trans ratios produced.13The observation that both ozonide and crossozonide cis'.trans ratios can be dependent on olefin geometry provides a powerful new probe for studying the mechanism of ozonolysis. Effective use of this(1) (a) Bell Telephone Laboratories, (b) On leave of absence from the Weizmann Institute of Science, Rehovoth, Israel,

The reaction of cyclohexanone with hydrogen peroxide to yield both the dimeric and trimeric cyclic peroxides has been investigated. It has been found that tricyclohexylidene peroxide is the kinetic product under most conditions and that dicyclohexylidene peroxide is easily formed from it. Improved syntheses of the peroxides, particularly for the trimer, have resulted.

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