10,l I-Dihydrocyclobuta[b]triphenylene and 1,2,5,6,9,1O-Hexahydrotriscyclobuta[ b,k,nltriphenylene[**I By R. L. Funk and K . P. C. Vo/lhardf[*l The synthesis and properties of various aromatic carbocycles fused to one strained ring have been the subject of considerable recent research activity. There are considerably fewer structures known consisting of two strained rings fused to an aromatic system. We now wish to report the synthesis of 1,2,5,6,9,10-hexahydrotriscyclobuta[b,h,n]triphenylene ( I ) , a benzenoid tetracycle to which three strained rings are symmetrically fused"]. For comparison model (41 with one annelated cyclobutane ring (10,l I-dihydrocyclobuta[b]triphenylene) was prepared by the iodine catalyzed oxidative photocyclization[31of 43diphenyl- 1,2-dihydro~yclobutabenzene[~~ followed by preparative thin layer chromatography (yield 82 38 conversion; m.p. 168-169°C). The structure assignment is based on the physical and chemical properties. Hydrogenation (Pt)leads to the phenanthrene derivative (5)l2] [m. p. 151-1 52"CI. (x, 'x (4) (51 The increasing strain in the series triphenylene, ( 4 ) and ( 1 ) is reflected in the physical and chemical properties of 131 Treatment of a concentrated (1.2 M) solution of 4-bromo-5iodo-l,2-dihydrocyclobutabenzenewith magnesium (room temperature; 12h) leads to a complex mixture of halogenated coupled products, in addition to the biphenylene derivative (3) and the desired triphenylene derivative (Z)[*]. The new cyclobutaarene ( I ) was obtained after repeated preparative thin layer chromatography on silica (3% ether in pentane) and fractional crystallization from ether as colorless plates (yield 0.5 'x)which decomposed above 260°C without melting. The structural assignment is based on the spectral and chemical properties [MS: m/e=306.1406 (calcd. 306.1408), M'; 'HNMR (CDCI,): T = 1.70 (s), 6.57 (s); electronic spectrum: Fig. 11. Hydrogenation with Pt (in ethanol) proceeds unusually rapidly to the partially hydrogenated benzene derivative (2)[2,61, a colorless oil ['H-NMR (CCI,): r=6.6-8.3 (m); UV (ether): h,,,,= 227 sh, 238 sh, 2701. these compounds. Thus, fusing one cyclobutane ring to triphenylene seems to lead to increased bond localization in one benzene ring as indicated in structure ( 4 ) . This is evidenced by the chemical shift for 4-H, 5-H (T= 1.32), intermediate between the corresponding absorptions in the phenanthrene derivative ( 5 ) (T = 1.25)and triphenylene (T = 1.44)15.']the , relatively high chemical shift for 9-H, 12-H ( T = 1.60) and the ease of hydrogenation of / 4 ) [ h 1Fusion . of three cyclobutane rings seems to result in increased bond fixation as suggested in formula (Z). The aromatic signals are shifted an additional 0.1 ppm to higher field due to the cumulative influence of three four-membered rings['], and hydrogenation is rapidIhl but leaves the central benzene ring intact. This is, of course, in striking contrast to the stringent conditions required to hydrogenate triphenyIeneI"! Finally, the electronic spectra (Fig. 1 ) exhibit strong bathochromic shifts along this series. Received: October 30. 1975 [ Z 344 IE] German version: Angew. Chem XH. 61 (1976) CAS Registry numbers ( 1 ) . 57674.78-9: (21. 57674-79.0: / . < J . 57674-xn-z: 141. S7674-81-3: ___ ( 5 ) . 57674-82-5 A dodecafluorohexahydrotriscyclobuta[~.c,i~]benzenehas been claimed, but no structural proof was provided: M. 0.Rile!. and J . 0. P a d . Tetrahedron Lett. IY71, 2871.  All new compounds gave satisfactory analytical andior spectral data.  F. B. ,!4rr//ori., C. S. Wood, and J. 7: GorrloJf. J. Am. Chem. Soc. N6, [I] 3094 (1964). K . P. C . Vo//hard~and R. G. Bergrimn, J. Am. Chem. Soc. YO. 4996 ( 1974). [ 5 ] R. If. ,Murfiii, N . Orfur. and F. Giwfs-Eirrrr.il, Tetrahedron 20. 1091 11964).  As shown by competition studies 4.5-diphenyl-1.2-dihydrocyclobutaben zene is not hydrogenated under these conditions.  The degree of bond fixation may be larger than indicated by N M R [S] [Y] :i 2 220 260 I I 300 A. [ n m l - 3LO Fig. 1. Electronic spectra of triphenylene (---J, in YS":, ethanol. I \\ 1 chemical shifts since hybridization  and ring current effects ( c . g . relative size of the ring currents of triphenylene. phenanthrene, benzene) may induce opposing trends. See Y. q. A . Srruirwirsru. G. R. Zieqlcr, P. C . Moiwrr. A . Lc'wi,. and R. G. Loidrr, J. Am. Chem. Soc. YO, 1357 11968). S. FrfrdJmJI. s. Mi,I/iri, A. swdi, and 1. We!fi/i,r. I. Org. Chem. 24, 1287 (1959): J. J. W h l . W R. K i r n r r . and N C . Hoii,uri/, J. Am. Chcni. and 1. M'iwdiv. J. SOC.67. 246 (1945): S. Friediififu, M . L. Ki/iffffIu~i. Org. Chem. 36, 694 (1971). , 380 ( 4 ) (.-....) . and ( I ) (- - - I [*] R L Funk and Professor Dr K . P. C . Vollhardt Departmem or Chemistry, University or California Degenerate Butadienylcyclopropane Rearrangement in Tricyclo[5.3.0.02~O]deca-3,5-diene By Klaus Heger and Wolfram Grimme['] We were recently able to show that above 110-C bicyclo[5.1 .0]octa-2,4-diene ( 1 ) undergoes degenerate butadienyl- Berkeley. California 94720 (USA) [**I This work rcas supported by thc Petroleum Research Fund, administered [*] Dipl.-Chem. K. Heger and Dr. W. Grimme by the American Chemic;il Society. the Research Corporation and the Energy Institut fur Orpanische Chemie der L'niversitat Reseal-ch and Development Administratioti. 5 Kiiln 41. Greinstrasse 4 (Germany) 53 cyclopropane rearrangement; of the two quantum mechanically "allowed" transition states having cisoid or transoid conformation only the latter is involved[']. However, the tricarbonyliron complex (2) having a fixed cisoid conformation formally undergoes the same rearrangement already at 90°Crz'. The metal apparently lowers the activation barrier for the geometrically less favorable process. We here report the butadienylcyclopropane rearrangement in tricycl0[126.96.36.199~~ 1°]deca-3,5-diene / 3 a ) whose cisoid geometry is fixed by the ethano bridge; no metal is involved in this rearrangement. O n treatment with thionyl chloride and tri-n-butylamine in ether, tricycl0[5.3.0.O~~'~]deca-3,5dien-9-01 (3b)'31 affords the chloride (3c), which is reduced directly by lithium tetrahydridoaluminate in boiling tetrahydrofuran without further purification. Gas chromatography of the resulting hydrocarbon mixture (3 m, 20 Reoplex on kieselguhr, 45ml He/min, 120°C) affords ( 3 a ) [17% based on (3b), retention time 7min; NMR (CDC13, TMS internal): ~ = 3 . 8(m) (2 olefinic H), 4.2 (m) (2 olefinic H), 6.9 (m) (7-H), 7.7-9.0 (m) (7 aliphatic H ) ; UV (dioxane): hm,,=267nm ( E =4200)] alongside the tetrahydroazulenes ( 4 ), ( 5 ) , and (6), probably formed by rearrangement of the chloride (3c). R2 R' R' = H , K~ = H (3b), R' = H,R 2 = OH (3aj, (3cj, R' = H,R2 = c1 ( 3 d ) , R'-H2 = 0 ( 3 e ) , R' = H , R~ = O ~ C - C ~ H , - C O ~ H /3f), K' = H ,R2 = 02C-C6H4-C02Q 0 (+)-H,N-CH( C H ~ ) - C S H ~ 141 a (5) 02 16i (3a) is stable up to 250°C in the gas phase-the degenerate rearrangement is not manifested by this compound-and undergoes uniform rearrangement to (6) at higher temperature. A homopentadienyl hydrogen shift of the endo 9-H rationalizes this process. Detection of the butadienylcyclopropane rearrangement was accomplished with the labeled compound [D5]-(3a) (the heavily drawn positions are deuterated) prepared in conventional manner : on H/D exchange of 2,4,6-cycloheptatrien-I ylmethyl diazomethyl ketoneI3' in [OD]-ethanol (20°C, pH 9) the diazomethyl position is labeled ; this site becomes position 10 in [D,]-(3u). Using the same technique (20"C, pH 14) the two a-methylene protons (8-H) are replaced in ( 3 d ) . Use of LiAID4 in the subsequent stepwise reduction of the ketone [D3]-(3d) leads to [D5]-(3u) [NMR (CDCI3, TMS internal): olefinic H as in (3a), ~ = 6 . 9 2 (t) (7-H), 8.4 (m) (I-H), 8.8ppm (m)(2-H)[41.Above 200°C [D,]-(Ja) undergoes butadienylcyclopropane rearrangement in the gas phase to 54 give its labeling isomer [D5]-(3'a) with which it equilibrates [NMR (CDCI3, TMS internal): olefinic H as in ( 3 a ) , z=6.92 (broadened t) (0.5 7-H), 8.4 (m) (I-H), 8.8 ppm (m) (2-H and 0.5 10-H)]. The rearrangement established for [D5]-(3a) by isotopic labeling converts ( 3 a ) into its mirror image (3'a). Because of the rather unproductive route to ( 3 a ) we have determined the kinetics of the rearrangement by polarimetry: (3b) is converted into the half-ester ( 3 ~ (40"/,, ) m.p. 117-119°C) by treatment with phthalic anhydride in pyridine; reaction of (3 e) with (+ )-a-phenylethylamine in ethanol/hexane (1 : 1) gives the salt (3f) (79"/,, m.p. 132--135°C). After four recrystallizations from ethanol/hexane (1 : 1) a fraction of constant melting point (46%, m.p. 141--142°C) is obtained, whose cleavage with 5 hydrochloric acid furnishes the half-ester (-)-(3e)["(75';/,, m.p. 119-121 "C). Reduction with LiAlH4 in ether gives the alcohol ( - ) - ( 3 b ) [97%, ,3°=-34.50 (in CHC13)] which is transformed into the chloride and reduced as described above. Gas chromatography of the product mixtureyields (-)-f3u) [14%, [ n y = - 10.0", [ ~ ] $ 8 ~ . , = = 19.5" (both in n-dodecane)]. Racemization of (-)-(3a) was followed up to a loss of at least 60% of rotatory power in 0.1 M dodecane solution at four temperatures between 179 and 193°C. Tetralin was added as an internal standard to the degassed samples which were then sealed into glass ampoules; each polarimetric measurement ( h = 407.7nm) was accompanied by a gas chromatographic loss analy~is'~! The racemization follows first order kinetics, and the temperature dependence of its rate constant is reproduced by the Arrhenius equation 'x logkz(13.53 *0.2)-(37800* 300)/2.303RT The free energy of activation of the butadienylcyclopropane rearrangement in (3a) is thus about 5.0 kcal/mol higher than that in (f)['I. Bearing in mind that ( I ) must first be transformed into its higher energy transoid conformer, the energy difference for the pericyclic reaction itself in the cisoid as against the transoid transition state should be taken as AAF* >6kcal/ mol. It remains to be established whether this difference is overcome also in the case of (3a) by coordination to the Fe(CO), group. Received: October 20. 1975 [Z 345 IE] German version: Angew Chem 88. 60 (1976) CAS Registry numbers: ( ? ) - / 3 ~ )57674-70-1 . : ( - ) - ( 3 < 0 ,57674-71-7: ( + )-/.?hI. 57674-72-3: ( - ) - i 3 b J . 57674-73-4; (?)-f.<c). 57674-74-5: ( 3 d j . 15719-07-0: ( ?)-(.?e)3 57674-75-6; ( - ) - / 3 e 1 . 57674-76-7: 131). 57759-53-2: (4). 57674-17-8: i s ) , 57739-04-5 W! Grimmie and M! 1'017 E . Doering, Chem. Ber. 106, 1765 (1973). R. Aionunn. Angew. Chem. 85. 628 (1973): Angew. Chem. Int. Ed. Engl. 12. 574 (1973). W w n E. Dowing, B. M . Frrrier. E. 7: Fossei. J . H . Hariensrriii, M Jones, Jr., C. Kluinpp, R. M. R u h m and M. Suunders, Tetrahedron 23, 3943 ( 1 967). Assignment of the signals corresponds to that established by double resonance for [ D 2 ] - ( 3 d )[ i ] The absolute configuration or ( - ) - ( 3 v l and its reaction products is unknown. the enantiomeric configuration ( 3 ' ) is just as likely. Losses never exceeded lo'?,,.