J . Am. Chem. SOC.1986, 108, 2113-2175 system, tungstenacyclobutane complexes are close in energy to alkylidene complexes, the actual species that predominates depending upon the extent of substitution of the tungstencyclobutane ring.
Scheme I O
Acknowledgment. R.R.S. thanks the National Science Foundation for support through Grant C H E 84-02892. C.J.S. thanks the Science and Engineering Research Council (U.K.) for a NATO postdoctoral fellowship. We also thank the Biomedical Research Support Shared Instumentation Grant Program, Division of Research Resources, for funds to purchase the X-ray diffraction equipment ( N I H Grant SlORR02243-01). Registry No. W(CBu-r)(NHR)(dimethoxyethane)CI,, 101347-96-0; W(CHBu-t)(NR)(dimethoxyethane)CI2, 101375-06-8; W(CHBu-t)(NR)(ORF)?, I O 1249-40-5; C H ~ C H & H ~ W ( N R ) ( O R F )I ~O ,1249-4 1-6;
W[CH(SiMe3)CH(SiMe3)CH2](NR)(ORF),, 101347-97-1; W(CBur)(dimethoxyethane)C13, 8341 6-70-0; Me3SiNH-2,6-C,H3Pr-i2, 7892365-6; LiOCMe(CF3)2,98171-13-2; W(CHEt)(NR)(OR,),, 101249-42-7; W(0)(NR)(ORF)2, 10131 5-93-9; ethylene, 74-85-1; tert-butylethylene, 558-37-2; vinyltrimethylsilane, 754-05-2; cis-3-hexene, 7642-09-3; trans-5,5-dimethyl-3-hexene, 690-93-7; eis-2-pentene, 627-20-3; cis-2butene, 590-1 8-1 ; trans-2-butene, 624-64-6; 3-hexene, 592-47-2; methyl oleate, 112-62-9.
Supplementary Material Available: Preparative, analytical, and spectroscopic details for all isolable compounds, along with final atomic coordinates and structure factor tables (31 pages). Ordering information is given on any current masthead page.
6-Cyanotetracyclo[5.5.0.02~4.03~s]dode~a-6,8,10, 12-tetraene: A Novel Heptalene Valence Isomer Yoshikazu Sugihara,* Shigeharu Wakabayashi, Naoki Saito, and Ichiro Murata*
Department of Chemistry, Faculty of Science Osaka University, Toyonaka, Osaka 560, Japan Received October 28, 1985 Recent research in this laboratory, beginning with the first synthesis of a pleiadiene isomer1 in 1973, has been directed toward attainment of a synthetic representation of valence isomers of nonalternant hydrocarbons. Among the relevant species are the azulene isomers la,* lb,32a: and 2b3 and the heptalene isomer 3,s*6which contain nonalternant pentafulvene and heptafulvene
12, X=OCH3
e,X=OCH,
12, X = H
Lb,X:H
2
?.
2113
. 7-
6,
+
cl
I
(qpqpqJ 0
!!
0
0
2
1.2
0
E
E
?!?
(a) 2.1 equiv of LiN(i-C3H7)C6Hllin THF-HMPA, then 2.2 equiv of PhSS0,Ph in T H F , 0 "C, 1 h, 45%; (b) 1.1 equiv of mCPBA in CH2C12, -30 "C, 3 h, 62%; (c) 1.1 equiv of mCPBA in CH2C12, -78 OC, 1 h, 84%; (d) 3.0 equiv of 1-lithio-2-vinylcyclopropanein etherT H F , -78 "C, 1 h, 96%; (e) 0.3 equiv of (MeO),P in benzene, 70 " C , 2.5 h, 77%; ( f ) 1.1 equiv of mCPBA in CH2CI2,-78 0 "C, 2 days, 65%; ( 9 ) 3.2 equiv of t-BuOK in ether, -78 OC, 1 h, 80%; (h) 2.8 equiv of n-Bu3P and 5.9 equiv of CCI, in CH2CI2,room temperature, 0.5 h, 88%; (i) 4.4 equiv of DBU in T H F , room temperature, 3 h, 90%; (j) 2.7 equiv of Me,SiCN, KCN/18-crown-6 complex in benzene, room temperature, 1 h, 99%.
-
plementary to those of the well-documented benzene isomers.* In this paper we disclose the successful synthesis and some properties of the fourth example of our series, 6-cyanotetracyclo[ 5.5.0.02,4.03,5]dode-6,8, 10,12-tetraene (cyan~heptalvalene)~ (4), which is significant since this carbon skeleton has recently been postulated as an intermediate in thermal heptalene-heptalene transformations1° but has never been isolated. The synthetic achievement completes a series of valence isomers of azulene and heptalene and opens the way for comparative studies on the detailed chemical and physical properties of these prototype molecules. Initially we planned to construct the bicyclobutane skeleton required for the synthesis of 4 through oxa-di-a-methane rearrangement" of an appropriately designed tricyclic &y-unsaturated ketone in an approach modeled after our previous synthesis of 2a4 and 2b.3 However, all attempts at these photoconversions gave unsatisfactory results. Consequently, in our successful approach (5),13which outlined in Scheme I,I2 tricyclo[4.1.0.02~7]heptan-3-one contains a bicyclobutane system, was used as a starting material.
chromophores,' respectively. Therefore, these studies are com(1) (a) Murata, I.; Nakasuji, K. Tetrahedron Lett. 1973, 47. (b) Pagni, R. M.; Watson, C. R., Jr. Ibid. 1973, 59. (c) For a Dewar-type isomer, see: Meinwald, J.; Samuelson, G. E.; Ikeda, M. J. Am. Chem. Soc. 1970, 92, 7604. (2) Sugihara, Y.; Sugimura, T.; Murata, 1. J . Am. Chem. SOC. 1982, 104, 4295. (3) Sugihara, Y.; Sugimura, T.; Murata, I. J. Am. Chem. SOC.1984, 106, 7268. (4) Sugihara, Y.;Sugimura, T.; Murata, I. J . Am. Chem. Soe. 1981, 103, 6738. (5) Sugihara, Y.; Wakabayashi, S.; Murata, I. J . Am. Chem. SOC. 1983, 105, 6718. (6) For a full paper on 1-3, see: Murata, I.; Sugihara, Y.; Sugimura, T.; Wakabayashi, S. Tetrahedron, in press. (7) Sugihara, Y.; Wakabayashi, S.; Murata, I.; Jinguji, M.; Nakazawa, T.; Persy, G.; Wirz, J. J. Am. Chem. SOC.1985, 107, 5894.
0002-1863/86/ 1508-2113$01.50/0
(8) (a) van Tamelen, E. E.; Pappas, S. P. J . Am. Chem. SOC.1963, 85, 3297. (b) Breslow, R.; Napierski, J.; Schmidt, A. H. J. Am. Chem. SOC.1972, 94, 5906. (c) Katz, T. J.; Wang, E. J.; Acton, N. J . Am. Chem. SOC.1971, 93, 3782. (d) Katz, T. J.; Acton, N. J . Am. Chem. SOC. 1973, 95, 2738. (9) We propose a trivial name 'heptalvalene" for the carbon skeleton of 4.
(10) Bernhard, W.; Briigger, P.; Daly, J. J.; Englert, G.; Schonholzer, P.; Hansen, H.-J. Helu. Chim. Acta 1985, 68, 1010. (1 1 ) Givens, R. S.; Oettle, W. F. J . Chem. SOC., Chem. Commun. 1969, 1164. Givens, R. S.; Oettle, W. F.; Coffin, R. L.; Carlson, R. G. J . Am. Chem. SOC.1971, 93, 3957. Givens, R. S.; Oettle, W. F. Ibid. 1971, 93, 3963. For a review, see: Hixon, S. S.; Mariano, P. S.; Zimmerman, H. E. Chem. Reu. 1973, 73, 53 1. (12) All new compounds described in this paper gave satisfactory IR, 'H NMR, and MS spectral data. Crystalline compounds are further characterized by combustion analyses. (13) Ipaktschi, J. Chem. Ber. 1972, 105, 1996.
0 1986 American Chemical Society
Communications to the Editor
2774 J. Am. Chem. SOC.,Vol. 108, No. 10, 1986 Scheme 11"
10%
trace
trace
15%
nil
(k) 4.8 equiv of POCI, and 0.5 equiv of 4-(dimethylamino)pyridine in pyridine, 60 OC, 3 h; (I) 7.1 equiv of P 0 C l 3 and 4.5 equiv of DBU in pyridine, 60 'C, 2-3 h.
Compound 5 was doubly sulfenylatedI4to 6 (an oil) in 45% yield by treatment with lithium cyclohexylisopropylamide and PhSS0,Ph. Oxidation of 6 with mCPBA followed by elimination of benzenesulfenic acid during workup gave 7 (mp 97-99.5 "C) in 62% yield. At this juncture, the next subgoal of the synthetic effort involved annelation of a seven-membered ring via Michael addition of an appropriate five-carbon unit. To this end, reaction of 7 with a mixture of cis- and trans- l-lithio-2-vinylcyclopropane'5 was examined. This reaction, however, led to the undesired 1,2-addition product. Therefore, 7 was first oxidized with mCPBA to give sulfoxide 8 (mp 121.5-123.5 "C) as an efficient Michael acceptor in 84% yield. Unlike 7, 8 was susceptible to a smooth Michael addition of the same reagent to yield the desired product 9 (an oil) in 96% yield which, without purification, on treatment with (Me0)3P in benzene at 70 "C gave the tetracyclic ketone 11 (an oil, 47% yield) through elimination of benzenesulfenic acid followed by Cope rearrangement, together with the uncyclized trans-cyclopropyl derivative 10 (an oil, 30% yield). With the tetracyclic ketone 11 in hand, completion of the synthesis required introduction of an additional double bond. Thus, compound 11 was converted into trienone 15 in the following manner. Regioselective epoxidation of 11 with mCPBA under controlled conditions gave epoxide 12 (an oil, bp 80 "C (bath temp) (0.1 torr), 65% yield). Ring opening of 12 with t-BuOK gave 13 (mp 126.5-127.5 "C) in 80% yield. Finally, treatment of 13 with n-Bu3P/CC1,16 in CHzClzgave 14 (mp 124-125 "C, 88% yield) which was dehydrochlorinated with DBU to afford a 4: 1 mixture of 15 and its double-bond isomer as an oil in 90% yield.I7 Introduction of nitrile functionality was effected by treatment of the mixture, without separation, with Me3SiCN and KCN/ 18crown-6 complex'* to give cyanohydrin silyl ether 16 (an oil) quantitatively. A few points in the last step (Scheme 11) require comment. Thus, usual treatment of 16 with POC1, in pyridineIg either in (14) Trost, B. M.; Salzman, T. N.; Hiroi, K. J. Am. Chem. SOC.1976, 98, 4887. (15) Piers, E.; Nagakura, I. Tetrahedron Lett. 1976,3237. Marino, J. P.; Browne, L. J. Ibid. 1976, 3245. (16) Downie, 1. M.; Holms, J. B.; Lee, J. B. Chem. Ind. (London) 1966, 900. Hooz, J.; Gilani, S . S . H. Can. J . Chem. 1968, 46, 86. (17) According to ' H NMR (CDCI,, 100 MHz) and IR spectra, the mixture consists of 15 (major) [ 6 7.23 ( 1 H, d, J = 6.0 Hz), 6.26 ( 1 H, dd, J = 9.3, 6.0 Hz), 5.60 ( 1 H, dt, J = 9.3, 6.8 Hz), 5.22 (1 H, t, J = 6.8 Hz), 2.82-3.10 (4 H, m), 2.28 (2 H, t, J = 6.8 Hz); vc4 1690 cm-l (s)] and its
-
isomer(minor)[66.72(1H,ddd,J= 11.0,5.5,
