2264 J. Org. Chem., Vol. 39, No. 15, 1974
Sheehan and Tulis
References and Notes ( 1 ) Taken from the dissertation of R . J. Michl, submitted to the Faculty of the Polytechnic Institute of Brooklyn in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemistry (1971). (2) T. Cohen, 14th Conference on Reaction Mechanisms, University of Vermont, Burlington, Vt.. June 13-16, 1972. (3) A. H. Lewin and R . J, Michl, J. Org. Chem., 38. 1126 (1973). (4) A. H . Lewin and T. Cohen, J. Org. Chem.. 32, 3844 (1967). (5) A . H . Lewin, A . H. Dinwoodie, and T. Cohen, Tetrahedron, 22, 1527 (1966). (6) D. F. DeTar and D. I . Relyea, J , Amer. Chem. Soc., 76. 1660 (1954). (7) E. L. Eliel, S. Meyerson, Z . Welvart, and S. H. Wilen, J.
(8) (9)
(IO) (11)
Amer. Chem. Soc.. 82, 2936 (1960); E. L. Eliel and J . S. Saha, J. Org. Chem., 30, 2451 (1965); E. L. E l k , 2 . Welvart, and S. H. Wilen, ibid., 23, 1821 (1958); E. L. Eliel, P. H. Wilken, F. T. Fong. and S. H. Wilen, J. Amer. Chem. Soc.. 80, 3303 (1958): E. L. Eliel, M. Eberhardt, 0. Simanura, and S . Meyerson, Tetrahedron Lett., 749 (1962); D. t i . Hey, M. J, Perkins, and G. W. Williams, J. Chem. Soc., 3412 (1964). The yield of benzophenone was corrected by subtracting the residual amount (5.6%) formed in the absence of dioxane. The yield of benzophenone was corrected by subtracting the residual yield (0.6%) formed in the absence of dioxane. Except for the increase in benzophenone at very iow pH values. R . G . R . Bacon and H . A. 0. Hiil, Quart. Rev.. Chem. Soc.. 19. 95 (1965).
Oxidation of Cyclic Amines with Ruthenium Tetroxide John C. Sheehan* and Robert W. Tulis D e p a r t m e n t of Chemistry, Massachusetts I n s t i t u t e of Technolog>, C a m bridge, Massachusetts
02139
Receiued M a r c h 12, 1974 T r e a t m e n t of 1,2-di-tert-butylaziridinew i t h r u t h e n i u m t e t r o x i d e gave N-iert-butyl-2.2-dimethylpropionamide. T h e r e a c t i o n involves several successive oxidations a n d intermediates, one of w h i c h c o u l d b e a n a - l a c t a m . T r e a t m e n t of a c y l a t e d cyclic amines w i t h r u t h e n i u m t e t r o x i d e gives l a c t a m s a n d / o r i m i d e s ,
T h e use of ruthenium tetroxide in the oxidation of orA carbon atom is lost during the reaction. Carbon dioxide can be detected a s a by-product of the oxidation. Carganic compounds is becoming increasingly more popular. bon monoxide is oxidized by ruthenium tetroxide only I t has been used primarily in the oxidation of alkenes to very slowly and in very low yield, indicating t h a t the caraldehydes, acids, or ketones,l alkynes t o a-diketones,2 pribon atom of the aziridine is lost as carbon dioxide. mary alcohols to a ~ i d s . l , secondary ~ alcohols t o ket o n e ~ , acyclic ~ , ~ ethers to esters, and cyclic ethers to lacA possible intermediate i n the oxidation of aziridine la is 1,3-di-tert-butylaziridinone(2a). When compound 2a t0nes.l Ruthenium tetroxide readily oxidizes aromatic systems, b u t is unreactive toward hydrocarbon^.^^^ Unwas treated with 1 equiv of RuOc, an 11%yield of amide 3 was obtained. This yield is increased to 77% with 4 usual oxidation insertion reactions have been reported in equiv of oxidant. Carbon dioxide was isolated in 91% the oxidation of osuloses6 and in the oxidation of a sterically hindered cyclopropanol t o a P-lactone in low yield.7 yield. T h u s it appears t h a t the a-lactam 2a is an intermeBerkowitz and Rylanderl applied ruthenium tetroxide diate in the oxidation of aziridine la. T h e effects of N-acylation and N-sulfonation were deoxidations to nitrogen-containing compounds. Unsubstitermined next. T h e results are shown in Table I for the tuted amines produced only intractable mixtures under following reaction. the reaction condition. Acyclic and cyclic amides were oxidized to imides in good yield. Prompted by these workers, we treated a series of cyclic amines from aziridine t o piperidine with ruthenium tetroxide. Essentially similar results were obtained as those rep0rted.l Since ruthenium tetroxide does not oxidize the nitrogen I atom directly, it should be possible to influence the oxidaR tion of amines by suitable substitution on nitrogen. lb-i 2b-i T h e results of N-alkylation were first determined. Treatment of l a with 1 equiv of ruthenium tetroxide gave a low yield (10%) of N-tert-butyl-2,2-dimethylpropionamide (3). I t appeared t h a t several successive oxidations were occurring and this was confirmed when a higher R yield of 3 was obtained with 4 equiv of oxidant. 5d,e
la
R = R'
2a
= tert-butyl
ri = 0
0
1I
only
T h e reaction is more likely to succeed the larger the ring size and seems to be effected by the electronegativity of the N substituent. It was also noted t h a t the rate of reaction decreases as ring size decreases and electronegativity increases. Different classes of compounds were oxidized preferably in a single-phase rather than a double-phase system. T h e single-phase system requires stoichiometric amounts of the oxidant. T h e major disadvantage of this procedure is that a large amount of solid ruthenium dioxide must be filtered from the solution and the desired product may become occluded in the solid, thereby decreasing the
J. Org. Chem., Vol. 39, No. 15, 1974 2265
Oxidation of Cyclic Amines with Ruthenium Tetroxide
0
Table I Per C e n t Y i e l d s of Lactamsa!b or Imidescsd O b t a i n e d from the O x i d a t i o n of Cyclic A m i n e s w i t h Ruthenium T e t r o x i d e
------_-____--
ROH PKB
n
R
0
1
2
3
e e
e e e
g CHaCO
e
i EtOCO
5b
22b la e 13b 9a 33b 15“
46 a 90” 34d 21c 68 7lC 34a 45b 69 a 65O
3-5” 85“ 74‘ 33c 59b 57c e 42 60a 63O
bp-MePhSOz c CHSSOz d CFSCO
e CH30COC0
f HCO
