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