ibid., 54, 2469 (1971).(22) (a) G. H. Whitham and M. Wright, J. Chem. SOC. C, 883 (1971); (b) ibid., 886 (1971): (c) ibid., 891 (1971). (23) The conformational barriers in the interconversion between the two diastereoisomers of cyclic Eallylic alcohols seem to resemble those to the racemization of optically active € cycloalkenes, except for the effect of the C,-hydroxyl substituent in the former. Some kinetic parameters for the racemization rates of (0-cyclooctene and (0-cyclononene, reported by Cope et al., are summarized in Table XI ((a) , J. Am. Chem. Soc., 87, 3644 (1965); (b) A. C. Cope and B. A. Pawson, ibid., 87, 3649 (1965)). Recently Whitham and Wright (ref 22) obtained the activation energy AH* = 35 kcal/mol at 170 OC for the thermal interconversion between the diastereoisomeric (l+cyclooct-2-en-1-yI acetates. This value is compatible with the value = 35.6 kcal/mol at 155 OC for the racemization of (0-cyclooctene. One can see also from Table XI that the longer is the methylene loop of cyclic Eallylic alcohols, the lower becomes the con-35 (1975). (28) The oxidation of secondary alcohols by the dioxovanadium (VO,' ) species In acidic aqueous solution is well known (W(1969), and references cited therein. (30) J. H.-H. Chan and 8. Rickborn, J. Am. Chem. SOC., 90, 6406 (1968).(31) The separation between u:p and u : ? (= Au) was also used as a measure of the length of the hydrogen bond for a series of cis and trans cyclic 1,Pdiols (L. P. Kuhn, J. Am. Chem. Soc., 76, 4323 (1954)). (32) Upon the magnetic anisotropic effect by oxirane ring; see, e.g., D. Lavie. Y. Kashman, and E. Glotter, Tetrahedron, 22, 1103 (1966). (33) It is well known that in the chair conformation of the cyclohexane ring, an axial proton resonances at higher field than the corresponding equatorial proton owing to the anisotropic effect exerted by the neighboring C-C single bond (L. The higher erythro-threo selectivity in the vanadium-catalyzed epoxidation Of acyclic allylic alcohols than in peroxy acid reactions also seems to be rationalized in terms of our transition state models, 111 and IV (cf. ref 7). (26) A. 0. .Abstract: Kinetic n secondar! deuterium isotope effects. k o / k H , for f o r m y l group transfer f r o m either the 4-methoxyphenql or 4-nitrophenyl esters, o r both, of formic and deuterioforinic acids to a variety o f oxygen acceptors have been measured at 25 O C i n aqueous solution: hydroperoxide ion. 1.12; 2-propynol anion, I . 13: hexafluoropropan-2-01 anion, 1.14; and water. I .22. I n addition, corresponding isotope effects have been obtained for general-base-catalyzed f o r m y l group transfer f r o m the same substrates t o acetate, I .21, formate. 1.23, and trimethylamine N-oxide, I .20.The n secondary deuterium isotope effect for acid-catalyzed hqdrolqsis o f both esters has been determined to be I .24. These data are interpreted to reflect considerable. and perhaps complete. carbon-oxygen bond formation i n the transition state for addition of oxygen nucleophiles to phenql formates. Finally. corresponding ...