410 J.C.S. Perkin IPhotochemical Behaviour of Bicyclo[6.3.l]dodec-1(11 )-en4 O-one.Crystal and Molecular Structure of 9,11 -Dibromotricyclo[6,3.1 .0135]-dodecan-I O-oneBy Bruno Gioia, Farmitalia, Ricerca Chimica, Via dei Gracchi 35, 20146 Milano, ItalyAlessandro Marchesini,' lstituto di Chimica lndustriale dell'universita', C.N.R. Centro di Studio sullaSintesi e Stereochimica di Speciali Sistemi Organici, Via Golgi 19, 201 33 Milano, ItalyGiovanni Dario Andreetti,' Gabriele Bocelli, and Paolo Sgarabotto, lstituto di Strutturistica Chimicadell'universita', C.N.R. Centro di Studio per la Strutturistica Difrattometrica, Via M. D'Azeglio 85, 431 00Parma, ItalyBicyclo[6.3.1]dodec-1(11 )-en-1 O-one undergoes photocyclization to give mainly tricyclo[6.3.1 .O1jS]dodecan-1 O-one.The crystal and molecular structure of 9.1 1 -dibromotricyclo[6.3.1 .01:6]dodecan-l O-one (6) wasdetermined by direct methods from diffractometer data and refined by least-squares techniques to R 0.067 for3 204 independent reflections.IN recent years, c$-unsaturated ketone photochemistryhas received a great deal of attenti0n.l The most widelyinvestigated group of compounds possessing this chromo-phore are substituted cyclohexenones, for which the typeof reactions found are strictly related to the substitutionpattern.Although 4,4-disubstituted cyclohexenones mainlyphotoisomerize to give bicyclo[3.1 .0]cyclohexan-2-ones,3the most frequently observed photochemical reaction isthe formation of cyclobutane dirner~.~Double-bond shifts due to intermolecular H-abstrac-tion, solvent incorporation, photoreduction,5 and intra-For recent reviews, see e.g.Chem. SOC. Specialist PeriodicalReports, Photochemistry, vols. I-V.a W. G. Dauben, G. W. Shaffer, and N. D. Wetmeyer, J . Org.Chem., 1968, 33, 4060.a For a review, see P. J. Kropp, Org. Photochem., 1967, 1, 67.For a review, see D. J . Trecker, Org. Photochem., 1969, 2, 71.D. Bellus, D. R. Kearns, and K. Schaffner, HeZv. Chim. A d a ,1969, 52, 971,molecular H-abstraction by the ketone oxygen,0 are alsofrequently observed. Direct H-transfer to the a-carbonof the enone system has recently been found in certaincyclohexenone derivatives.' The photoisomerizationof taxinine and some of its derivatives follows a formallysimilar H-transfer, but a concerted addition has beenenvisaged as the most likely mechanism.8We have reported9 the photochemical behaviour ofbicyclo[9.3.l]pentadec-l(14)-en-13-one, and explainedthis reaction as being the result of a H-transfer from thepolymethylene chain to the p-carbon of the enonesystem. We now report the photochemistry of bicyclo-[6.3.l]dodec-l(ll)-en-l0-one ( Z ) , and show that this- 8 A.B. Smith and W. C . Agosta, J . Org. Chem., 1972,87. 1259.'I J. Gloor and K. Schaffner, Helv. Chim. A d a , 1974, 57, 1815.8 T. Kobayashi, M. Kurono, H. Sato, and K. Nakanishi, J.A. Marchesini, U. M. Pagnoni, and A. Pinetti, TetrahedronAmer. Chem. Soc., 1972, 94, 2863.Letters, 1973, 42991977 41 1photoisomerization is an entry of synthetic utility to thetricyclo[6.3.1 .01.6] dodecane system.The title compound was prepared from cyclonon-2-enone lo in 65% overall yield as shown in Scheme 1.n ,CO,E tHC.0 0 It( 1 1SCHEME 1(2) 0When the enone (2) was irradiated in benzene solutionwith a high-pressure Hg lamp through Pyrex, twophotoproducts, (3) and (4), were formed in ca.1 : 6 ratio.The yields of these materials were high (80% at 1.871 0 - 4 ~ concentration) and decreased with increasingconcentration, owing to the formation of dimeric pro-ducts. The two products were isolated by silica gelcolumn chromatography. Details of procedures andweights of chromatographic fractions are given in theExperimental section. A study of product distributionvs. extent of irradiation established that the ratio (3) : (4)was constant as a function of time.The spectral data of(3) and (4) are very similar, elemental analysis and massspectrum indicate the composition C1,H,,O, isomeric0(4) (6 1SCHEME 2Reagents: i, Br,; ii, Zn-AcOHwith the starting material. The n.m.r. spectrum showsabsence of olefinic hydrogens, hence (3) and (4) must betricyclic compounds.Irradiation was also carried out for different solvents,and considering the time required for completion ofreaction, the reactivity decreases as follows : propan-2-01, acetone, methanol, benzene, cyclohexane.The ratio of the major product (4) to the minor (3)showed a slight solvent dependence. Ratios were 6 : 1for reactions in cyclohexane, benzene, and acetone,8 1 for propan-2-01, and 9 : 1 for methanol.Bromination of (4) affords a dibromoketone (6).1.r. and n.m.r.data suggest an aa'-dibromo-ketonestructure with the two bromine atoms axial.Reduction of the dibromide (6) with Zn in AcOHaffords the parent ketone (4). These data establish thepresence in (4) of -CH,-CO-CH,- system and suggestthat the tricyclic system in (4) arises from bond form-ation between C ( l ) and either C(4), C ( 5 ) , or C ( 6 ) . Theexact structure was determined by an X-ray diffractionanalysis of (6).If one assumes a stepwise reaction, hydrogen abstrac-tion by the ketone oxygen and directly by the a-carbonof the enone system are possible primary photochemicalprocesses.One possible mechanism of cyclization , H-abstractionby carbonyl oxygen, was eliminated by the observationthat the irradiation in CH,OD solution did not afforddeuteriated (4).Also, examination of models showedconsiderable strain for this abstraction. For the form-ation of (4) from (2) we therefore suggest Scheme 3.SCHEME 3The structure of (3) is still under examination. Spec-tral data suggest it may be a stereoisomer of (4). Bro-mination affords a non crystalline mixture of cis- andtrans- a, a'-dibrom oke t ones.The formation of both the photoketones (3) and (4)was found to be completely quenched in the presence ofoxygen. This fact, together with the previously reportedsolvent effects, suggests that a triplet excited state of(2) is involved.In propan-2-01 another product (5) was formed (25%)and was identified as bicycl0[6.3.l]dodecan-lO-one onthe basis of analytical and spectral data; it was identicalwith the dihydro-derivative of (2) obtained by catalytichydrogenation. The ring junction was proved to becis by reduction with LiAlH,: from (5) two isomericalcohols, (7a) and (7b) in a 5 : 1 ratio, were obtained.Molecular Geometry of 9,1 l-DibromotricycZo[6.3.1 .0135]-dodecan-l O-ont? (6) .-The Figure shows the projectionof the structure on (100) and the numbering system used15) (7a,b 1SCHEME 4Reagents: i, H,-Pd; ii, hv, propan-2-01in the crystal structure analysis.There are two inde-pendent molecules in the asymmetric unit and the cor-responding bond distances and angles (Table 1) and theconformation are not significantly different.A similar tricyclic system has already been found inlo N.Heap and G. H. Whitham, J . Chem. SOC. ( B ) , 1966, 164412 J.C.S. Perkin ITABLE 1Bond distances (A) and angles (") in (6)(a) Distances ::[;;z;$ O( 1 )-c(1)C(l)-C(2)C(2)-C(3)C(3)-C(4) c (3)-c (9)C( 4) -C( 5)C(5)-C47)C(7)-C(8)C(9)-C I 10)C(lO)-C(11)C(ll)-C(12)O( I)*( 1)<?(2)W 1C(2)-C(l)-C(6)Br ( 1 )-C(2)-C ( 1 )Br ( 1 )-C (2)-C 3 )C( 1 )-c (2)-C (3)C(S)-C (3)-C (4)c (2)-c(4)-C ( 12) c (4)-c (3)-c(9)c f 3)-C(4)-C (5)c (41-c (5)-c (6 1C(4)-C(5)-C(7)C(6)-C(5)--C(7)W2)-C(6)-C(1)C( l)-C(6)-C(5)C(7)-C(8)-C(9)C(3)<(9)-c/8)C(3)-C(9)-C( 10)C( 8)<( 9)-C (1 0)C(9)-C( lO)-C(ll)c(lo)-C(ll)-c(l2)C( 1)-C(6)C(3)<( 12)C( 5)-C (6)C( 8)-C (9)(b) AnglesC(2)-C(3)-C(9)C(4)<(3)-C( 12)C(9)-C(3)-C(12)Br (2)-C ( 6 ) s (5)C(5)-C(7)<(8)C (3)<(12)-C( 11)Molecule (1 )1.988(7)1.97'1 (.7)1.2 14(9)1.506( 10)I .516( 10)1.513(10)1.56 L(10)1.546( 10)1.546(9)I .50 1 ( 1 1)1.562( 10)1.506( 12)1.541 (9)1.504(11)1.570(12)1.517( 11)1.535( 10)120.4( 11)120.9(12)118.5( 11)102.8(6)112.6(7)11 7.0( 1 1)11 1.0(10)I 09.3( 10)109.9( 10)112.4(10)115.4( 10)98.2 (8)108.I (9)11 1.4( 10)1 I1.7(10)107.0( 7)I14.0(11)113.1(11)11 1.7(9)1 06.1 ( 10)120.9( 12)103.3(10)106.5(11)104.6(10)110.0( 11)110.9(8)110.1(11)Molecule (2)1.989(7)1.2 1 1 (8)1.5 15( 9)1.504( 10)1.525(9)1.523(9)1.565( 10)1.520(9)1.562(9)1.519(11)1.545( 11)1.525(10)1.525(9)1.504(10)1.543 (9)1.497( 10)1.990(7)120.3(10)I20.9( 1 1)118.8(10)1 04.2(6)112.1(7)117.8(10)108.5(10)112.9(10)117.2( 10)97.2 (8)108.5(9)109.6( 10)1 1 1.8( 10)109.5( 1 1 )106.9(7)110.2(7)114.6( 11)114.6( 11)109.3( 10)1 12.8( 10)105.3(9)120.5( 1 1)104.3( 9)105.5( 9)106;.6(9)110.1(9)1 10.0( 10)TABLE 2Equations of least-squares planes in the tricyclododecanesystem of compound (6), in the form IX + mY + nZ -- p whereX, Y, and 2 are related to the crystallographic orthogonal axesby the transformation matrix :1 0 cosp (: A :in@)Distances (A x lo3) of relevant atoms from the planes aregiven in square brackets; values for molecule (2) follow those formolecule (1)Plane (,4): C(9)-(12)0.9586X -f- 0.2010Y - 0.20192 = -3.3479-2.1019 -0.9618X - 0.1621Y - 0.22072 =[C(3) 701, 695: C(9) -7, - 8 ; C(l0) 13, 12; C(11) -13,-12; C(12) 7, 81Plane ( B ) : C(3), C(5), C(7), C(9)0.7284X + 0.5151Y - 0.45102 = -1.4072-0.7496X - 0.4306Y - 0.51732 = -2.1538(C(3) 19, 20; C(4) -724, -710; C(5) -24, -24; C(7) 26,29; C(8) 647, 644; C(9) -21, -241Plane ( C ) : C(2), C(:3), C ( 5 ) , C(6)--0.3728X $- 0.4936Y - 0.78582 = --0.3096-0.9269 0.3688-Y - 0.3581 Y - 0.85782'=[C(1) 301, 296; C ( 2 ) 25, 28; C(3) -27, -29; C(4) -746,-756; C(5) 29, 32; C(6) -27, -311pseudoclovene-A-diol,ll a rearrangement product ofcaryophyllene, but while in compound (6) the fusionbetween the five- and six-membered rings is trans, in the0d9 P(a)(blProjection of the structure on (100); (a) molecule f l ) and(b) molecule (2)TABLE 3Torsion angles (")C(6)-C( 1)-c(2)-C(3)c ( 1 )-C(2)-C(3)-C(9)C (2)-C ( 3 ) X (4)-C (5)C (9)-c (3)-c( 4)-C (5)C \ 12) -C (3)-C (4)-C(5)C(2)-C(3)-C(9)-C(8)C (2)-C (3)-C( 9)-C I 10)Cf4)-C(3)-C(9)-C(8)C(4)-C(3)-C(9)-C( 10)C( 12)-C(3)<(9)<(8)C( 12)-C(3)-C(9)-C( 10)C(2)<(3)-C( 12)-C( 11)C14)-C(3)-C( 12)-C( 11)C(9)<(3)<(12)-C( 11)C (3)-C(4)-C(5)-C (6)C(2)-Cf l)-C(6)-C(5)C(l)-C(2)-C(3)-C(4)C( 1)<(2)-C(3)-C(12)C(3)-C(4)-C(5)-C(7) :[$3:;Z[:;z{: ; C(4)-C(5)-€(7)-C(8)C(6)-€(5)-C(7)-CP3)C(5)-C(7)-€(8)-C(9)C(7)-C(8)-C(9)-C(3)C(7)-Cf 8)-C(9)-€(10)C(3)-C(9)--C(lO)-C(ll)C(8)-C(9)-C(lO)-C(ll)C(lO)-C(l l)-C( 12)-C(3)C(9)<( lo)<( 11)-C(12)Molecule (1)23.6-27.4- 40.3- 171.281 .O60.3- 60.6- 170.4- 61.372.860.6-- 165.7- 178.5- 44.9- 72.4159.142.457.648.4- 65.9- 76.2-54.270.251.2- 54.4179.729.5158.0-2.0- 26.2Molecule (2)23.5-27.8- 40.180.360.8-173.1-58.7- 168.4- 59.973.460.6- 166.2- 177.1-43.8- 70.9159.642.7-66.155.548.4- 74.6- 52.868.950.7-54.1- 179.529.0157.9-2.0-26.8case of pseudoclovene it is cis.The cyclohexane ringadopts a chair and the cyclopentane ring an envelope11 D. M. Hawley, G. Ferguson, T. F. W. McKillop, and J. M.Robertson, J. Ckem. SOC. (B), 1969, 5991977 413conformation. The cyclohexanone ring adopts a chairarrangement but deviates from the ideal conformation,the ring being flattened because of the sfi2 character ofatom C(1).The two bromine atoms are cis and axial.The reciprocal orientation of the ring in the two mole-cules can be deduced from an analysis of planarity andfrom the torsion angles (Tables 2 and 3). The dihedralangles between planes ( A ) and ( B ) , and (C) and (D) are153.3 and 153.0, and 109.7 and 109.0" in molecules (1)and (2) respectively. Carbon-hydrogen bonds are inthe range 0.95(7)-1.09(7) A, mean 1.02(1) A. Packingis consistent with van der Waals interactions.EXPERIMENTALMethods and i"ClateriaZs.-I,r. spectra were recorded on aPerkin-Elmer 377, 1H n.m.r. spectra in [2H]chloroformsolution with a Varian HA 100 or A 60 A spectrometer.Chemical shifts are given in 6 from tetramethylsilane asinternal standard and refer to the centre of the signal.U.V.spectra were recorded for 96% ethanolic solutions on aBeckmann DB GT spectrometer. Mass spectra wereobtained with a Perkin-Elmer 270 GC Ms system, at anionizing potential of 70 eV, using the gas chromatographicinlet. G.1.c. analyses were run on a Pye series 104 chromato-graph [dual glass column; ( A ) 2 m x 3 mm, packed with5% EAS on 100-120 mesh silanized Chromosorb W,nitrogen flow 40 ml min-l; (B) 1.7 m x 3 mm, packed with5% QFl on 100-120 mesh silanized Chromosorb W,nitrogen flow 40 ml min-'1. Column chromatography wasperformed on Merck Kieselgel 60, 0.063-0.200 mni.T.1.c. was carried out using Merck Kieselgel F,,,.Mag-nesium sulphate was used as drying agent. Evaporationwas carried out in vacuo (rotary evaporator). Irradiationwas carried out with a 125 W HPK Philips high-pressurcHg lamp.Immersion-well apparatus. This consists of a water-jacketted Pyrex well housing a 125 W lanip. The well fitsinto a cylindrical 400 ml reaction vessel equipped with aninlet for gas and an outlet for the removal of aliquotportions.In a typical irradiation experiment, ketonewas dissolved in the appropriate solvent, and the solutionplaced in the reaction vessel, which was held in placearound the immersion-well apparatus. Nitrogen wasbubbled through the solution for 15 min before irradiation.Aliquot portions were periodically withdrawn to ascertainthe extent of reaction.Ethyl 2-( 3-0xocycZononyZ)acetoacetate (1) .-To a mixtureof cyclonon-2-enone lo (20 g) and ethyl acetoacetate (20.7 g)a solution of EtONa in EtOH [from Na (300 mg) and EtOH( 5 ml)] was added.After 12 h at room temperature, thereaction mixture was diluted with Et,O (200 ml), washedwith water (2 x 50 ml), and dried. In vacuo distillationof the residue from the solvent evaporation afforded (l),b.p. 144-146 "C a t 0.5 mmHg (34 g, 87.5y0), vmx. (film)1740 and 1705 cm-l; 6 4.2 (2 H, q, CO,CH,Me),3.44 [0.5 H, d, J 7 Hz, -CH(CO,Et)COMe], 3.48 [0.5 H, d, J8 Hz, -CH(CO,Et)COMe], 2.4 (4 H, m, -CH,COCH,-),2.26 (3 H, s, -COCH,), and 1.28 (3 H, t, -COOCH,CH,).BicycZo[6.3.l]dodec-l( ll)-en-lO-one (2) .-Ethyl 2-(3-0~0-cyclonony1)acetoacetate (1) (34 g) was added to a mixtureof AcOH (170 ml), H,O (100 ml), and H,SO, (25 ml).Thesolution was heated under reflux for 4 h. After cooling,Irradiation.water (500 nil) was added and the mixture extracted withn-pentane (3 x 100 ml). The organic layer was dried.The residue from the solvent evaporation was distilled invacuo affording (2) (16.9 g, 74.7%), b.p. 110 "C at 0.5niniHg, vmx. (film) 1 675 and 1 625 cm-'; Amx. 242 ( E 12 630)322 (E 51), 5.88 (1 H, s, =CHCO-).Irradiation of BicycZo[6.3.l]dodec-l(ll)-en-lO-one (2).-(a)In bemzene. In a typical run the ketone (2) (1 g) was dis-solved in benzene (300 nil) and irradiation carried out for5 h. Solvent was removed by rotary evaporation.Theresidue from three runs, distilled in vacuo, afforded 2.4 g,b.p. 94-100 "C at 0.5 nimHg. G.1.c. [ ( A ) , 150 "C] showedtwo products: (3) 14.3o/b and (4) 85.7%. Silica gel (70 g)column chromatography (eluant n-hexane to n-hexane-Et,O 10: I v/v) afforded a mixture (857 mg) of (3) and (4)(42 and 58% respectively), and (4) (1.40 g), b.p. 98-100 "Cat 0.6 mmHg; v , , ~ ~ . (film) 1 710 cm-l; 6 2.3 (4 H, m) and1.95 (2 H, m); m/e 178 (M+) (59), 149(24), 135(40), 134(75),122(17), 121(100), 120(56), 109(8), 108(21), 107(22) 95(27),94(23), 93(49), 92(22), 91(40), 81(28), 79(62), 77(28), 67(38).55(26), 53(24), 41(49), and 39(34).Column chromatography of the mixture of (3) and (4) onsilica gel (50 g) (eluant n-hexane to n-hexane-Et,O 10: 1v/v) afforded (3) (150 mg), b.p.87-90 "C at 0.4 mmHg;vmx. (film) 1710 cm-'; n.ni.r. spectrum inconclusive; m/e178 (M+)(76), 149(7), 135(89), 134(58), 122(24), 121(100),120(74), 109(29), 108(18), 107(26), 95(60), 94(23), 93(51),92(18), 91(36), 81(24), 79(62), 77(24), 67(53), 55(29), 53(24),41(60), and 39(45).Irradiation was carried out for 3 h,as previously described. The residue from three runs,distilled in vacuo, afforded 2.8 g, b.p. 90-95 "C at 0.4mmHg. G.1.c. [ ( A ) , 150 "C] showed three products:(3) 8.3%, (4) 66.7%, and (5) 25%. Silica gel (80 g) columnchromatography (eluant n-hexane to n-hexane-Et,O, 10 : 1v/v) afforded a mixture ( 1.8 g ) of (4) and (5) (69 and 31 yorespectively). Compound (5) (320 mg), b.p. 92-94 'C a t0.4 mmHg, was obtained by preparative g.1.c.(2 m x 6 mmglass column, QF1 5%, silanized Chromosorb W 60-80mesh, 18fi0, nitrogen flow 180 ml niin-1) ; vmax. (film) 1 708cm-l; n.m.r. spectrum was inconclusive; m/e 180 ( M t ) ( 7 ) ,137(4), 109(7), 95(100), 81(5), 68(11), 67(14), 55(20), and41(22)'.Irradiation in the Presence of Oxygen.-Bicyclo[6.3. I]-dodec- 1 ( 1 1)-en- 10-one (2) (40 mg) was dissolved in benzene(10 ml), in a Pyrex test tube, and oxygen bubbled throughthe solution for 5 min. The solution was then photolysedfor 2 h. A probe in benzene, degassed with nitrogen, wasalso photolysed simultaneously. Product analysis by g.1.c.showed only a trace of (4) [ < 0.1 yo].BicycZo[6.3.l]dodecan- I 0-one (5) .-Hydrogenation of bi-cyclo[6.3.1]dodec-l(11)-en-lO-one (2) was carried out with5% Pd-C as catalyst.In a typical run the ketone (2)(356 mg) was dissolved in AcOMe (30 ml) and 5% Pd-Ccatalyst (30 mg) added to the solution. Hydrogenationwas then carried out at room temperature under atmos-pheric pressure until all the ketone (2) had disappeared asshown by g.1.c. (ca. 30 min). Catalyst was then filtered offand solvent evaporated. Vacuum distillation afforded (5)(330 nig) identical with a sample obtained from (2) byirradiation in propan-2-01.9,1 l-DibromotricycZo[6.3.1 .01~6]dodecan-10-one (6) .-To asolution of (4) (400 mg) in CH,Cl, (40 ml), Br, (380 mg) inCH,CI, (10 ml) was added during 5 min. After solventevaporation, the residue was crystallized from n-pentane-(b) In propan-2-oZ414 J.C.S.Perkin IEt20 and shown t o be (6), 520 mg, m.p. 107 OC; vmX.(Nujol) 1715, (CCl,) 1720 cm-1; 6 4.1 (2 H, m), 2.95(1 H, d, J 13 Hz), 2.5 (1 H, m), 2.3 (1 H, m); m/e 338(5),336(10), 334(5), 257(24), 255(25), 175(30), 147(12), 133(1 1),121(100), 119(20), 91(23), 79(19), 67(13), 41(13).TricycZo[6.3.1 .O1fjdodecaut-lO-one (4) from the Dibromide(6).--Zinc powder (400 mg) was added to a solution of thedibromide (6) (200 mg) in AcOH (10 ml). After 30 min a t80 OC, water' (30 ml) was added and the mixture extracted7.24(1), b = 14.90(1), c = 22.61(1) A, 8 = 93.0(2)', 2 = 8,D, = 1.83 g ~ m - ~ , U = 2 435.7 Hi3. Cu-K, radiation,A = 1.541 8 A; ~(CU-K,) = 91.3 cm-l. Space groupP2Jc from systematic absences.lntensity data were collected on a Siemens single-crystaldiffractometer up t o 0 70" by use of the 0-20 scan methodand the five-points technique l2 (nickel-filtered Cu-K,radiation).Of 4 577 independent reflections measured,3 204 were used in the crystal analysis, having intensitiesTABLE 4Fractional co-ordinates ( x lo4; x lo3 for H atoms) with standard deviations in parenthesesX171(1)66412)28618)-738(11)- 1 715(10)- 3 567110)-3 541(11)-3 125(12)-1 209(11)- 4 576( 12)-4 780(11)-5 369112)- 4 855( 12) - 4 375( 11)- 185(8)- 239( 10)- 466\9)-317(10)-642(9)-429(9)-583(9)- 582(9)- 362(9)- 663(9)- 598(9) - 383(9)-32519)--633(9)-5 109(11)-101(9)- 443(9)Molecule (1)Y4 77211)2 665( 1)4 807(4)4 380(5)4 837(6)3 438(5)3 148(5)3 41815)3 535f6)4 539(6)4 820(5)5 790(6)5 813(6)4 867(5)4 45315)549(4)334(4)316(5)319(5)244(5)452 (4)338(4)322(4)476(5)484(5)62 l(4)602(4)60415)627(4)488(4)454 (5)z3 158(1)2 261(1)1 680(2)1 982(3)2 488(3)2 644(3)2 624(3)1988(3)1 836(3)1 520(3)1558(3)2 20013)2 359(4)3 042(4)3 217(3)239(3)288(3)276(3)141 (3)197t3)231(3)111(3)158(3)129(3)142(3)213(3)223(3)327(3)314(3)338(3)355(3)X-2 326(1)-3 004(7)-1 836(10)-3 117(1)-703(10)1 222(10)1 190(11)58 1 (1 1)1831111)2 044( 11)2 587(11)2 875(11)2 613(12)-1 411(11)2 131(11)--53(9)29(9)248(9)387(9)72W141(9)314(9)86(9)294(9)191(9)403f9)154(9)376(9)338(9)127(9)- 167(9)Molecule (2)Y1 748f1)4 077( 1)2 112(4)1890(4)2 225(4)3 238(5)3 691(5)3 442(5)2 398(5)1978(5)78 1 ( 5 )1 663(5)127(4)340(5)365t4)226(4)367(5)368(4)216(4)225(4)63(5)77(4)3415)52/4)197(5)159(4)2 457(5)3 409(5)98 1 (5)344(5)437(4)Z527(1)- 113( 1)- 920(2)-591(3)- 15013)48(3)- 464(3)- 634(3)- 965(4)- 1 040(3)-441(3)- 386(3)138(3)274(3)543(3)44(3)2W3)-43(3)- 32 (3)- 109(3)-3113)- 136(3)- 88(3)- 120(3)- 135 (3)-66(3)-51(3)34(3)47(3)71(3)87(3)with n-hexane (3 x 50 ml).Usual work-up afforded (4)BicycZo[6.3.1]dodecan-lO-oZ (7a and b) .-To a solution ofbicycio[6.3.l]dodecan-l0-one (5) (250 mg) in dry Et,O(40 ml), LiAlH, (53 mg) was added during 3 min.After1 h at room temperature, water was added (1 ml) and theorganic layer dried. Silica gel (20 g) column chromato-graphy (eluant n-hexane to n-hexane-Et20, 8 : 1 v/v) of theresidue from the solvent evaporation afforded (7a) [181 mg,b.p. 105-110 "C at 0.1 mmHg, m.p. 62 "C; vmax. (Nujol)3 360 cm-l; 6 4.16 (1 H, m, -CHOH)] and (7b) [45 mg,b.p. 105-110 "C a t 0.1 mmHg, n1.p. 70 "C; vmax. (Nujol)3 280 cm-l; 6 4.03 (1 H, m, -CHOH)].Crystal Structure of 9,l l-DibromotricycZo[6.3.1 .0135]-dodecan- 10-one (6) .-Crystals are colourless prisms, elon-gated on [loo]. Preliminary cell dimensions and space-group data were obtained from oscillation and Weissenbergphotographs. Lattice parameters were refined by a least-squares fit of 14 (O,X,rp)hkl measurements taken on a Siemenssingle-crystal diffractometer.C,,H,,Br,O, M = 336.1.Monoclinic, a =(74 "€9.Crystal data.l2 W. Hoppe, Acta Cryst., 1969, A25, 67.l 3 A. J . Wilson, Nature. 1942, 150. 151.2[a2(1) + 12]112, where 1 is the relative intensity and02(1) its variance. The dimensions of the crystal used inthe analysis were 0.3 x 0.4 x 0.8 mm in the x , y , z direc-tions. Absorption was ignored.Data were put on anabsolute scale by Wilson's method l3 and normalizedstructure-factor amplitudes were derived. The structurewas solved from 499 reflections with IEl >, 1.59. The basicset was chosen using the programme MULTAN l4 and an Emap, computed by using the most consistent set of signs,revealed the position of four bromine atoms. A structure-factor calculation carried out at this stage gave R 0.30.The remaining non-hydrogen atoms were located from asubsequent Fourier calculation. The structure was refinedby block-diagonal least-squares cycles first with isotropicand then with anisotropic thermal parameters, reducing Rto 0.085. A difference-Fourier synthesis was then com-puted and revealed significant residual peaks near the posi-tions where the hydrogen atoms were expected to occur. Afew least-squares cycles with unit weights were thenl4 P. Main, M. M. Woolfson, and G. Germain, MULTAN, Acomputer program for the automatic solution of crystal struc-tures. 1971, University of York.Structure analysis and refinement1977 415computed including the hydrogen atoms with isotropic ref. 16 for hydrogen. Observed and calculated structure-thermal parameters, and giving a final I? factor of 0:067. factors and thermal parameters are listed in SupplementaryFinal positional parameters together with their standard Publication No. SUP 21886 (21 pp., 1 microfiche).*[6/966 Received, 21st May, 19761 deviations are given in Table 4. Atomic scattering factorsused were from ref. 15 for non-hydrogen atoms and froml5 D. T. Cromer and J . R. Mann, Acta Cryst., 1968, AM, 321. * See Notice to Authors No. 7, in J.C.S. Perkin IT, 1975, Index l6 R. F. Stewart, E. R. Davidson, and W. T. Simpson, J . Chem.issue. Phys., 1965, 42, 3175