J. Org. Chem., Vol. 43, No. 16, 1978 3163
3,5-Dinitroperoxybenzoic Acid SOC.,87, 1320 (1965). (10)J. P. Dirlam, L. Eberson, and J. Casanova, J. Am. Chem. SOC.,94, 240 (1972). (11) (a) A. R . Miller, J. Org. Chem., 41,3599 (1976),and references therein; (b) H. M. R. Hoffmann, Angew. Chem., lnt. Ed. Engl., 12,819 (1973);(c) E. A. Schmidt and H. M. R . Hoffmann. J. Am. Chem. SOC., 94, 7832 (1972). (12)C. A. Vernon, J. Chem. SOC.,423 (1954). (13)(a) F. G.Bordwell, Acc. Chem. Res., 3,281 (1970):(b) F. G.Bordwell and M. W. Carlson, J. Am. Chem. SOC.,92,3370,3377 (1970):(c) F. G.Bord(d) F. G.Bordwell, M. W. well and J. Aimy, J. Or,&!.Chem., 38,575 (1973); Carlson, and A. C. Knipe, J. Am. Chem. SOC.,91, 3949 (1969). (14)(a) It is conceivable that the key intermediate in the formation of the aacetoxy ketones is not oxyallyl cation 27 but rather an allene oxide,14b though we re rd the latter as unlikely for reasons similar to those advanced by Bordwell:lg nevertheless, we are presently carrying out an experimental search for such interme!diates;lk (b) B. S.Ong and T. H. Chan, Tetrahedron Lett., 3257 (1976);(c) Y. Migron, research in progress. (15)(a) R. A. Sneen, J. Am. Chem. Soc.. 83,900(1961):(b)R. H. De Wolfeand W G. Young, Chem. Rev., 56, 753 (1956).
(16)A. J. Fry, "Synthetic Organic Electrochemistry", Harper and Row, New York, N.Y., 1972,Chapter 5. (17)H. Budzikiewicz, C. Djerassi, and D. Williams, "Mass Spectrometry of Organic Compounds", Holden-Day, San Francisco, Calif., 1967,p 168. (18)F. W. Mcbfferty, "Interpretation of Mass Spectra", 2nd ed,W. A. Benjamin, 1973. (19)Program written by A.J.F. (20)Reference 17,p 237. (21)Reference 17,p 443. (22)J. Levy and P. Jullien, Bull. SOC.Chim. Fr., 45,941 (1929). (23)A. Sosa, Ann. Chim.(Paris),[ll], 14, lOO(1940). (24)"Handbook of Chemistry and Physics", 47th ed,Chemical Rubber Publishing Co., Cleveland, Ohio, 1966,p C-194. (25)A referee has commented that thermal conductivity detector response factors were not established, thus introducing some inaccuracies into the data of Table I; while this is correct, it is unlikely that conclusions reached herein would be affected in any substantive way i f this omission was corrected. In point of fact, whenever analyses were feasible by both NMR and VPC, the results agreed quite closely (f2-5% ). (26)C. Prevost and A. Sommiere, Bull. SOC.Chim. Fr., 2, 1151 (1935).
3,5-I)initroperoxybenzoic Acid. A Crystalline, Storable Substitute for Peroxytrifluoroacetic Acid William H. Rastetter,* Thomas J. Richard, and Michael D. Lewis Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 Received January 27,1978 Epoxidati,ons a n d Baeyer-Villiger oxidations by 3,5-dinitroperoxybenzoicacid preparation of 3,5-DNPBA is also given.
In the course of our syntheses of sym-oxepin oxidesla-d we were required to effect the difficult epoxidations of olefins l a and lb. Neither peroxytrifluoroacetic acid epoxidation nor high-temperature epom idation by m -chloroperoxybenzoic acid proved preparatively useful in these systems. Under optimized conditions only low conversions of l a and l b to the corresponding epoxides could be achieved with peroxytrifluoroacetic acid. Buffered (Na2C03 or Na2HP04) peroxytrifluoroacetic acid reaction mixtures gave, a t best, intractable mixtures of starting material, desired epoxide, and unidentified by-products.2 Treatment of the parent system l a with 4,4'-thiobis(6-tert-bul,y1-3-methylphenol) (tbp)3 stabilized m -chloroperoxybenzoic acid a t elevated temperatures led to tarry reaction mixtures and low yields of diepoxide 2a.la Clean, efficient epoxidation of l a was achieved using p -nitroperoxybenzoic acid, stabilized by t b ~ in, ~1,2-dichloroethane a t 90 "C (yield of crystalline 2a, 65%).la With the substituted derivative lb, however, the optimized yield utilizing p-nitroperoxybenzoic acid did not exceed 37%.2We have found that 3,5-dinitroperoxybenzoic acid (3,5-DNPBA) is an efficient reagent for achieving the conversion lb .- 2b (vide infra).4 Herein we report on the synthetic utility of 3,5DNPBA for difficult epoxidations and Baeyer-Villiger oxidations. ROOC
ROOC
2a 2b
la rb l a and 2a, R = C:H,CCl,;
lb
and
2b, R
= CH,CCl,;
R' = H R',R' = -CH,CH,CH,-
(3,B-DNPBA) are described. A
Results and Discussion T o test the utility of 3,5-DNPBA we have chosen as substrates la, lb, and several other olefins or ketones for which literature %xidationprocedures exist. Our results and a summary of literature oxidations are presented in Table I. An inspection of the table suggests that 3,5-DNPBA is not as reactive as peroxytrifluoroacetic acid (e.g., compare concentrations and reaction times for ethyl crotonate) but shows that yields for oxidations by these two peroxy acids are comparable. I t should be noted that similar weights of precursor per mole of peroxy acid are needed for 3,5-DNPBA and peroxytrifluoroacetic acid. The procedure for generation of methylene chloride solutions of peroxytrifluoroacetic acid5 utilizes trifluoroacetic anhydride (mol wt 210.03) and hydrogen peroxide; buffers are routinely utilized to remove the trifluoroacetic acid which is also formed. By our procedure, crystalline samples of 3,5-DNPBA with active oxygen content >90% can be easily made from 3,5-dinitrobenzoic acid (mol wt 212.12). Advantages of 3,5-DNPBA over peroxytrifluoroacetic acid are (1)no buffers are needed in 3,S-DNPBA oxidations and (2) 3,5-DNPBA can be stored for long periods without significant loss of active oxygen content. We have routinely stored 3,5-DNPBA in a freezer (
