1419
Communications to the Editor
product sublimed into a trap cooled by liquid nitrogen and was found to be more than 95% pure by I3C NMR. The structure proof for 1 is based on the mass spectrumlla (m/e 146 ( M f ) ) , the IR spectrumIia ( v 3040 cm-I), the IH N M R spectrum ((C6D6) 6 2.36-1.06 (multiplet and two distinctive doublets at 6 2.12 and 1.08, J = 4 H z " ~ ) ) ,and the I3C N M R spectrum ((C6D6) 6 64.4 (d, J = 166 Hz, 1 C; c-5),50.1 (t, J = 129Hz, 1 C; C-10 or C-6), 40.9 (dd, J = 151 and 169 Hz, 1 C; C-3), 44.0 (d, J = 138 Hz, 2 C; C - I , C-9), 34.2 (t, J = 128 Hz, 2 C; C-8, C-1 l ) , 30.8 (t, J = 129 Hz, 1 C; C-6 or C-IO), 26.6 (d, J = 133 Hz, 1 C; C-7), and 24.2 (s, 2 C; C-2, C-4)). The C-H coupling constants of the I3C NMR dd signal a t 6 40.9 are typical of the methylene carbon in the bicyclobutane system.') In the I3C N M R spectrum of 2,4-methano3,3-d2-2,4-dehydroadamantane ( la)I2 this signal is absent, which strongly supports the structure proof for 1. The chemistry of 1 is in accord with the structure of smallring propellanes. At room temperature 1 decomposed slowly even in benzene solution under a nitrogen atmosphere. It reacted rapidly with oxygen and instantly with moisture, methanol, and bromine to give complex mixtures of product^.'^ With carbon tetrachloride 1 reacted instantaneously a t room temperature yielding 100% single product (398% pure by GLC), the spectral datal5 of which indicated that it was 2chloro-4-trichloromethyl-2,4-methanoadamantane (4). Compound 4 was thermally stable [bp 1 I O OC (0.01 mm)] and inert to bromine (at 20 OC for 24 h). Hydrogenolysis of 1 with Pd/C in benzene solution a t 20 "C and 1 atm produced 2methyladamantane ( 5 ) as the major product (290%).17 Interestingly, the central bond in 1 appears not to be cleaved in the first step, since this would lead to the stable 2,4-methanoadamantane.
*
cm-'; MS m/e 162 (M+, 59%), 134 (29), 119 (28), 105 (43), 93 (IOO),92 (100). 91 (100). (11) (a)MSm/e 146(Mf,65%), 131 (85), ll8(60). 105(91), 104(83),92(46), 91 (100); IR (KBr) v 3040 (m), 2905 (s), 2850 (m), 1462 (m), 1450 (m), 1190 (m), 1070 (m), 1020 (m) cm-'. (b) These doublets are absent in the 'H NMR spectrum of 2,4-methano-3,3-d2-2,4-dehydroadamantane (la).l2 (12) Compound l a was prepared by pyrolysis of the tosylhydrazone sodium salt of 4-methylene-d2-2-adamantanone. (13) Stothers, J. B. "Carbon-13 NMR Spectroscopy"; Academic Press: New York, 1972; p 335. 14) The study of the chemistry of 1 is in progress and will be published in a full paper. 15) ' 3 C N M R ( C ~ D ~ ) 6 1 0 5 . 1 ( S , 1 C ) , 6 2 . 4 ( s , 1 C ) , 5 7 . 3 ( s , 1 C ) , 5 1 . 4 ( d , J = 145 Hz, 1 C), 43.0 (dd, J = 140 and 146 Hz, 1 C),16 39.2 (d, J = 138 Hz, 1 C), 35.8(dd. -, 1 C), 34.0(t, J = 128 Hz. 1 C), 31.3(d, J" 135 Hz, 1 C), 31.0 (t. J = 126 Hz, 1 C), 27.2 (t, J = 126 Hz,1 C). 24.9 (d, J = 135 Hz,1 C); 'H NMR (CC14) 6 3.05-1.25 (multiplet and two distinctive doublets'sat 6 2.64 and 2.23, J = 9 Hz); IR (neat) u 3010 (m),16 2920 (s), 2855 (m), 1465 (m), 1450 (m), 1157 (s), 920 (m), 890 (s), 783 (s), 760 (s) cm-'; MS d e 298 (M+, 5%), 300 (6), 302 (3), 264 (loo), 262 (loo), 229 (45). 227 (70), 115 (50). 91 (79), 79 (73), 77 (83). 16) This sianalb) Is absent in the soectrum of 2-chloro-4-trichloromethyl' 2,4-m~hano:3,342-adamantane'(obtained from la). 17) The product was identified by comparing its 13C NMR, 'H NMR, IR, and mass spectra with those of an authentic sample of 2-methyladamantane. 18) Sasaki, T.; Eguchi, S,;Hirako, Y. J. Org. Chem. 1977, 42. 2981. 19) Hoffmann, R. J. Am. Chem. SOC.1968, 90, 1475. Bodor, N.; Dewar, M. J . S.;Wasson, J . S. Ibid. 1972, 94,9095. (20) Udding, A. C.; Strating, J.; Wynberg, H.;Schlatmann, J. L. M. A. Chem. Commun. 1966,657.
Katica MlinariC-Majerski, Zdenko Majerski* Rudjer BoSkoGiC Institute, 41001 Zagreb Croatia, Yugoslaljia Received July 23, I979
Primary Quantum Yields of Ketyl Radicals in Photoreduction by Amines. Abstraction of H from N Sir:
1 5 G The carbene center in 4-methylene-2-adamantylidene (2) is not "ideally" s i t ~ a t e d for ' ~ the intramolecular cycloaddition to the olefinic bond. The angle between the axes of the carbene center p orbital and the olefinic bond p orbitals is -60". The arrangements of the carbene center and the 7-CH bonds in 2 and 2-adamantylidene are essentially equal, and the latter inserts readily into the T-CH bonds.20 Nevertheless, 2 yields exclusively the intramolecular cycloaddition product, 1.
Acknowledgments.This work was supported by the Research Council of the Republic of Croatia (SIZ 11). We thank Dr. Z. Meit for recording the 13C N M R spectra. References and Notes (1) Presented in Dart at the 6th Meetina of Chemists of Croatia, Feb 1979, Zagreb, Yu oslavia (2) Pentacyclof5.3.1 .0i.402~5.04~9]undecane. (3) Wiberg, K. 6.; Burgmaier, G. J. J. Am. Chem. SOC.1972, 94,7396; Tetrahedron Lett. 1969, 317 (4) Aue, D. H.; Reynolds, R. N. J. Org. Chem. 1974, 39,2315, and references therein. (5) The hybridization of the central bond in carbocyclic [1.1.11-, [2.1.11-. [3.1.
