Received: December 27, 1977; [Z 908 IE]

German version: Angew. Chem. 90,216 (1978) revised: January 20, 1978

CAS Registry numbers: ( I J , 38963-97-2; ( 1 J , radical anion, 65636-00-2; ( 3 J , 65635-99-6; (3J, radical anion, 65701-69-1 ; (4J, radical anion, 65701-70-4

See, e.g., R . B. Woodward, R . Hoffmann, Angew. Chem. 81, 797 (1969); Angew. Chem. Int. Ed. Engl. 8, 781 (1969). S. F . Nelsen, J . P . Gillespie, J. Org. Chem. 38, 3592 (1973); J. Am. Chem. SOC. 95, 2940 (1973); N. L. Bauld, J . Cessac, C . S . Chang, F . R. Farr, R . Holloway, ibid. 98, 4561 (1976). E. Vogel, Pure Appl. Chem. 20, 237 (1969). E. de Cleur, Ph. D. thesis, Universitat Koln 1969. J . A. Berson, M . R . Willcott I l l , J. Am. Chem. SOC. 87, 2752 (1965); 88, 2494 (1 966). a) E. Vogel, personal communication; b) G . Jabs, Ph. D. thesis, Uni- versitat Koln 1971. These parameters agree within the limits of error with the corresponding values in ref. [Sb]. Experimental details, in particular those concerning the ESR and ENDOR spectra, will be published in a forthcoming paper. F. Gerson, E. Heilbronner, W A. Boll, E . Vogel, Helv. Chim. Acta 48, 1494 (1965). This finding also permits unequivocal assignment of the coupling con- stants to the two sets of four equivalent ring protons in The assignment of the coupling constants to the eight single ring protons in ( 3 p e is largely based on correlation with n-spin populations calcu- lated according to the McLachlan procedure [ A . D. McLachlan, Mol. Phys. 3 , 233 (1960)l. F . G . Kliirner, unpublished work, quoted in ref. [Sb]. In contrast to ( 1 )-e where the additional electron occupies the lowest antibonding orbital of one butadiene n-moiety, in ( 5 p e such an electron enters the nonbonding orbital of the nonatetraenyl n-system. The differ- ence in rr-energies (0.62p in the HMO model) would facilitate the opening ofthe three-memberedring in the radical anion [ ( I J.e+(5)*e] relative to the neutral compound [ ( l J + ( 5 Y ] and thus lower the activation energy.

Regioselective Synthesis of Isomeric Bicyclic Peroxides[**]

By Waldemar Adam, A . John Bloodworth, Henny J . Eggelte, and Mark E . Loueittr]

Monocyclic peroxides ( 1 ) have recently been shown to serve as useful synthons for the preparation of unusual organic molecules1']. Equally importantly they constitute valuable pre- cursors of the mechanistically interesting diradicals[']. The geometrical contraint in bicyclic peroxides (2) is expected to impart new synthetic and mechanistic behavior, but unfor- tunately no general and convenient methods are presently available for the preparation of such compounds.

n

of non-conjugated cyclic dienes with hydrogen peroxide and mercury bis(trifluor0acetate) (peroxymercuration) followed by reduction with NaBH4I3], and b) photooxygenation of conju- gated cyclic dienes followed by reduction with azodicarboxy- lateC41.

These complementary and regioselective peroxybicycliza- tions are illustrated for the saturated compounds 9,lO-dioxabi- cyclo[3.3.2]decane (1,5-epidioxycyclooctane) ( 6 a ) and 7,8- dioxabicyclo[4.2.2]decane (1,4-epidioxycyclooctane) (6 b) , re- spectively.

n n-0

When the diene (3a) was added to a mixture of hydrogen peroxide (85-95 %) and mercuric trifluoroacetate in CHZC12 at room temperature, equal amounts of the bicyclic peroxide ( 4 ) and the corresponding bicyclic ether were formed [use of Hg(N03)2.H20[31 in this particular case affords only the ether]. The products were separated by dissolving the mixture in benzene, whereupon crystals of the pure (solvated) peroxide were precipitatedc5]. Reduction of ( 4 ) in CH2Clz with NaBH4 in aqueous NaOH gave the previously unknown cyclic perox- ide (6 a)[61, together with an approximately equal amount of 4-cycloocten-1-01. Catalytic hydrogenation of ( 6 a ) over Pd/C led quantitatively to the known cis-1,5-cyclooctane- diolr7], m.p. 73-75°C.

On the other hand, photooxygenation of the diene ( 3 b ) in CH2C12 with tetraphenylporphyrin as sensitizer gave the known['] unsaturated peroxide ( 5 ) , which on reduction with azodicarb~xylate[~] in methanol afforded the previously unknown saturated peroxide (6 bjC9]. Catalytic hydrogenation of (6b ) over PdjC gave quantitatively the known cis-1,4-cy- clooctanediol["], m.p. 81-83 "C.

For the first time saturated bicyclic peroxides with medium- sized rings have become conveniently available from readily accessible starting materials. Furthermore, ( 6 a ) is the first bicyclic peroxide to be prepared that does not contain a 1,2-dioxane ring.

Received: December 27, 1977 [Z 91 1 IE] German version: Angew. Chem. 90, 216 (1978)

In this communication we describe potentially general routes to isomeric bicyclic peroxides involving: a) reaction

[*] Prof. Dr. W. Adam [+I, Dr. H. J. Eggelte Department of Chemistry, University of Puerto Rico Rio Piedras, Puerto Rico 00931 (USA) Prof. Dr. A. J. Bloodworth, Dr. M. E. Loveitt Christopher Ingold Laboratories University College, London WCIH OAJ (England)

['I Author to whom correspondence should be addressed. [**I We acknowledge the financial support of the National Institute of Health to W. A., the Science Research Council to M. E. L., and a Fulbright- Hays travel grant and a visiting professorship from the University of Puerto Rico to A. J . 8 .

[l] W Adam, Angew. Chem. 86, 683 (1974); Angew. Chem. Int. Ed. Engl. 13, 619 (1974).

[2] W Adam, J . Sanabia, Angew. Chem. 85, 914 (1973); Angew. Chem. Int. Ed. Engl. 12, 843 (1973); L. Salem, C . Rowland, ibid. 84, 86 (1972) and J I , 92 (1972), respectively.

131 A. J . Bloodworth, M . E. Loveitt, J. Chem. SOC. Chem. Commun. 1976, 94; 3. Chem. SOC. Perkin I 1978, in press.

141 W Adam, H. J . Eggelte, Angew. Chem. 89, 762 (1977); Angew. Chem. Int. Ed. Engl. 16, 713 (1977).

[S] Solvated ( 4 J was isolated in 42 % yield, m.p. 118-1 19°C (dec.); elemen- tal analysis indicated the presence of 0.81 equivalents of benzene. NMR (CDCls, TMS): 6=128.6 (CeH,), 85.3, 48.4, 34.1, 29.1.

[6] ( 6 a J was isolated in 25 % yield by chromatography on SiO2/CH2CI2, and purification by fractional sublimation (45"C/15 torr); m.p. 116- 118°C; 'H-NMR (CCI.,, TMS): 6=1.50-2.30 (m, 12H) 4.35-4.65 (m, 2H); "C-NMR (CDCls,TMS): 6=83.96,31.38,23.82; MS: m/e= 142 (7 %), 55 (100).

209 Angew. Chem. Int. Ed. Engl. 17 (1978J No. 3

171 M.p. 73.8-74.8OC: A . C. Cope, A. H. Keough, P. E . Peterson, H. E . Simmons, G. W Wood, J. Am. Chem. SOC. 79, 3900 (1957).

[8] Y Kayama, M . Oda, Y Kitahara, Chem. Lett. 1974, 345. 191 ( 6 6 ) was isolated in 20% yield by chromatography on SiO2/CHCI3,

and purification by fractional sublimation (45 T / I O torr); m.p. 96- 98°C; 'H-NMR (CCI4, TMS): 6 = 1.25-2.45 (m, 12H), 4.20-4.60 (m, 2H); I3C-NMR (CDC13, TMS): 6=76.02, 34.60, 24.46, 20.68; MS: m/e=142 (9%), 55 (100); the multiplet of the 12 methylene protons is less symmetrical than in ( 6 a ) .

[lo] M.p. 83.2-84°C; A . C . Cope, J . M . Grisar, P. E . Peterson, J. Am. Chem. SOC. 81, 1640 (1959).

Trapping of Unstable Fulvene/Singlet Oxygen Adducts by Reduction with Diazene[**l

By Waldemar Adam and Ihsan Erden[*]

We recently reported that diimide (diazene) selectively re- duces thedouble bond in the unstable endoperoxides (1 a ) and (I b) , derived respectively from singlet oxygenation of cyclo-

pentadiene"] and 1,4-dimethylnaphthalene['b], without sever- ing the labile peroxide linkage. This novel, selective reduction should constitute a convenient and effective chemical tool for the characterization of unstable endoperoxides derived from singlet oxygenations since the basic peroxide skeleton is pre- served. Furthermore, it offers a unique entry into unusual and hitherto inaccessible cyclic peroxides. We demonstrate the feasibility and potential of this methodology with the unstable peroxides ( 3 a ) and (3b) , formed from 6,6-dimethyl- and 6,6-diphenylfulvene, respectively.

Singlet oxygenation of 6,6-disubstituted fulvenes (2) leads to a complex mixture of products, postulated to be derived

[*I Prof. Dr. W. Adam (NIH Career Development Awardee, 1975-1980), Dr. I. Erden Department of Chemistry, University of Puerto Rico Rio Piedras, Puerto Rico 00931 (USA)

I*'] Cyclic Peroxides, Part 64. This work was supported by the Petroleum Research Fund (Grant 8341-AC-l,4), administered by the American Chemical Society, the National Science Foundation (Grant CHE-72-04956-A-04) and the National Institutes of Health (Grants GM-22119-02, GM-00141-02, and RR-8102-04).-Part 63: W Adam, A. J . Bloodworth, H . J . Eggelte, M . E. Loueitt, Angew. Chem. 90, 216 (1978); Angew. Chem. Int. Ed. Engl. 17, 209 ( 1 978).

from the labile epidioxyfulvene (3) by rearrangementc2]. NMR evidence for the intervention of (3) could be secured when the singlet oxygenation was carried out at -70°C; but above - 20°C the unstable (3) afforded the previously observed complex product mixture[31.

On treatment of a CH2C12 solution of ( 3 a ) , prepared from 6,6-dimethylfulvene (2 a) by photo-oxygenation at - 78 "C with tetraphenylporphyrin as sensitizer and a General Electric 400W sodium lamp, with diimide which was generated in situ at -78°C as described previously['"], the stable cyclic peroxide ( 4 a ) was isolated in 63% overall yield as white needles (m.p. 53 "C) after recrystallization from CH2C12/ CH30H (1:3). Structural proof for ( 4 a ) rests on satis- factory elemental analysis, spectral dataI4] and chemical transformations. Thus, reduction with thiourea in CH30H at 0°C gave the diol ( 5 ~ ) [ ~ ' , which could be dehydrated back to the fulvene ( 2 a ) on refluxing in acetic acid for one hour. On treatment with triethylamine in CH2C12 at O T , ( 4 a ) is converted into (7a)L61.

Similarly, (2 b ) gave the cyclic peroxide ( 4 b ) in 88% overall yield on photo-oxygenation and diimide reduction at - 78 "C, m.p. 77-78°C (from 2:1 C6H6/CH30H)"1. The reactions of the phenyl derivatives ( 4 b)+(6 b)[*I and ( 6 b)+ (2 b ) could be accomplished under the same conditions as used for the methyl derivatives. ( 4 b ) can be converted into (7b) by treat- ment with methanolic KOH at O"C[91.

Ozonolysis of ( 3 a ) and ( 3 b ) in CH2C12 at -78°C in the presence of tetracyanoethylene produced an unstable sub- stance which exhibited proton resonances at 6=2.0 (m, 4H) and 4.38 (m, 2H), besides acetone and benzophenone. When the ozonolyzate was allowed to warm up to -10"C, the substance decarbonylated cleanly into succinaldehyde (8) . On the basis of these facts we assign the compound the novel epidioxyketone structure (5 ) . Interestingly, ( 5 ) decarbony- lates with emission of light; it can therefore be regarded as a "energy reservoir".

Received: January 23,1978 [Z 912a IE] German version: Angew. Chem. 90,223 (1978)

CAS Registry numbers: ( 2 a ) , 2175-91-9; ( 2 b ) . 2175-90-8; ( 3 a ) , 51027-90-8; ( 3 6 ) , 65651-42-5; ( 4 a ) , 65651-43-6; ( 4 b ) , 65651-44-7; (5). 65651-45-8; ( 6 a ) , 65651-46-9; (66), 65651-47-0; ( 7 a ) , 65651-48-1; ( 7 6 ) , 65651-49-2; ( 8 ) , 638-37-9; diazene, 3618-05-1

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121

131

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r61

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a) W Adam, H . J . Eggelte, J. Org. Chem. 42, 3978 (1977); b) Angew. Chem. 89, 762 (1977); Angew. Chem. Int. Ed. Engl. 16, 713 (1977). W Skorianetz, K . H . Schulte-Elte, G. Ohlo#, Angew. Chem. 84, 311 (1972); Angew. Chem. Int. Ed. Engl. 11 ,330 (1972); N . Harada, S . Suzuki, H. Uda, H. Ueno, J. Am. Chem. SOC. 94, 1777 (1972). N . Harada, H . Uda, H . Ueno, S:I. Utsumi, Chem. Lett. 1973, 1173; N . Harada, S . Kudo, H . Uda, S . Utsumi, ibid. 1974, 893. ( 4 a ) , 'H-NMR (CC14, TMS): 6=1.80 (s, 6H), 1.5Cb2.15 (m, 4H), 4.58 (m, 2H); IR (CCI4): 2990, 2960, 2875, 1470, 1360, 1270, 1180 m-' ; MS: m/e=140. ( 6 a ) , h. p. 93-95°C (from CH30H/Ether (l : l)) , yield 84%; 'H-NMR (CDC13, TMS): 6=1.90 (s , 6H), 1.75-2.00 (m. 4H). 2.35 (br. m, 20H), 4.75 (m, 2 0-C-H). ( 7 a ) , b. p. 78"C/0.4 torr; nBo=1.5050; yield 76%; 'H-NMR (CDC13, TMS): 6=1.7&2.70 (m. 4H), 2.05 and 2.30 (s, 6H), 2.60 (m, OH), 4.94 (m, 0-C-H). ( 4 b ) , 'H-NMR (CC14, TMS): 6=1.95 (m, 4H), 4.65 (m, 2H), 7.10 (br. s, 10H); IR (CCI4): 3100, 2980, 1470, 1435, 1210, 1025, 900 cm-' ; MS: m/e = 264. ( 6 b ) , m. p. 148-149°C (needles from CH30H/H20) ; yield 88%; 'H- NMR (CD30D, TMS): 6=1.60 (m, 4H), 4.30 (m. 2 0-C-H), 4.48 (s, 20H) , 6.97 (br. s, 10H). ( 7 b ) , m.p. 163-164°C (dec.) (from C H 3 0 H / H 2 0 (3:l)); yield 66%; 'H-NMR (CDC13, TMS): 6=1.78-2.85 (m, 4H), 1.96 (m, OH), 4.82 (m, 0-C-H), 7.20(m, 10H).

210 Angew. Chem. I n t . Ed. Engl. 17 (1978) No. 3