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Highly Diastereoselective Synthesis and Epoxidation of Chiral 1 2-Dihydronaphthalenes.

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(cyclic voltammetry and differential pulse voltammetry) indicated a single oxidation (n = two electrons, by coulometry). Similarly, careful spectroelectrochemical studies at - 32 "C in acetonitrile solution provided no evidence for the transient
accumulation of a Ru",Ru"' state. Accordingly, the Ru",Ru"'
form of these complexes appears to be thermodynamically disfavored with respect to disproportionation.
These results indicate a weak interaction between the metal
centers and are consistent with results reported recently for a
complex in which the bridging ligand is composed of two diazofluorene units linked by an adamantane spacer.['*] As noted
previously,['*. "1 such weak interactions do not preclude the
existence of rapid intercomponent energy or electron transfer,
and photophysical studies are in progress on Ru/Ru, Ru/Os,
and Os/Os analogues of the complexes described here to assess
the consequences of spatial separation on such processes.
Received : April 29, 1996 [Z 9078 IE]
German version: Angew. Chem. 1996, i08.2651-2653
Keywords: cycloadditions * cyclopentadienones
reactions ruthenium compounds
-
Diels-Alder
[l] A. Juris, S. Barigelletti, S. Campagna, V. Balzani, P. Belser, A. von Zelewsky,
Cool-11. Chem. Rev. 1988, 84, 85.
[2] a) L P . Sauvage, J.-P. Collin, J.-C. Chambron, S. Guillerez, C. Coudret, V.
Balzani, E Barigelletti, L. Decola, L. Flamigni, Chem. Rev. 1994, 94, 993;
b) K. S. Schanze, K. Sauer, J Am. Chem. SUC.1988, ff0,3180; c) L. F. Cooky,
S. L. Larson, C. M. Elliott, D. F. Kelley, J. PIij,s. Chem. 1991. 95, 10694;
d) C . K.Ryu, R. Wang, R. H. Schmehl, S. Ferrere, M. Ludwikow, J. W. Merkert, C. E. L. Headford, C. M. Elliott, J. Am. Chem. Soc. 1992, f 14,430;e) S. L.
Mecklenburg, B. M. Peek, J. R. Schoonover, D. G. McCafferty, C. G. Wall,
B. W. Erickson, T. J. Meyer, ibid. 1993, 115, 5479; f) K. A. Opperman, S. L.
Mecklenburg, T. J. Meyer, Znorg. Chcm. 1994, 33, 5295.
[3] J. Bolger, A. Gourdon, E. Ishow, J.-P.-Launay, J. Chem. Soc. Chem. Commun.
1995,1799;M. J. Crossley, P. L. Burn. S. J. Langford, J. K. Prashar, ibid. 1995.
1921.
[4] R. N. Warrener, M. A. Houghton, A. C. Schultz, F. R. Keene, L. S. Kelso, R.
Dash, D. N. Butler. Chem. Commun. 1996, 3151.
[5] M:T. Youinou. N. Rahmouni, J. Fischer, J. A. Osborn. Angew. Chem. 1992,
104, 771; Angew Chrm. Ini. Ed. Engl. 1992, 3 f , 733; P. N.W. Baxter, J.-M.
Lehn, J. Fischer, M.-T Youinou, ihid. 1994, 106, 2432 and 1994, 33, 2284.
[6] J. M. Lawson, D. C. Craig, A. M. Oliver, M. N. Paddon-Row, Tetrahedron
1995,51, 3841; K. Kumar, R. J. Tepper, Y. Zeng, M. B. Zimmt, J. Org. Chem.
1995, 60, 4051, and references therein.
[7] a) R. N. Warrener, S. Wang, L. Maksimovlc, P. M. Tepperman, D. N. Butler,
Tetruhedron Lett. 1995, 36, 6141 ; b) R. N. Warrener, G. M. Elsey, M. A.
I
Clirm. Soc. Chem. Cornmun. 1995. 1417; c) R. N. Warrener, G.
Houghton, .
Abbenante, R. C. Solomon. R. A. Russell, Tetrahedron Lett. 1994, 35, 7639:
d) R. N. Warrener, L. Maksimovic. G. M. Elsey, D. N. Butler, 1 Chem. Soc.
Chem. Commnn. 1994,1831 ; e) R. N. Warrener, G. Abbenante, C. H. L. KenG. Pitt, E. E.
nard, J. A m . Chetn. Suc. 1994, 116, 3645; f) R. N. Warrener, I.
Nunn, Tetruhedron Lett. 1994, 35, 621; g) R. N. Warrener, Chem. Aust. 1992,
59, 578; 11) R. N. Warrener, P. Groundwater, I.G. Pitt. D. N. Butler, R. A.
Russell, Tetrahedron L e f t . 1991, 32, 1885; i) R. N. Russell, Terrahedron Lett.
1991, 32, 1885; i) R. N. Warrener, D. A. Evans, R. A. Russell, ibid. 1984, 25,
4833; j) D. N. Butler. P. M. Tepperman, R. A. Gau, R. N. Warrener, W. H.
Watson, R. P. Kashyap, ihid. 1995, 36, 6145.
[8] R. N. Warrcner, I. G. Pitt. D. N. Butler, J. Chem. Sue. Clienz. Commun. 1983,
1340.
V. Sankar, D. N. Butler, P. Pekos, C. H. L.
[9] a) R. N . Warrener, G. M. Elsey, I.
Kennard, Eiruhedron L e f t . 1994, 35, 6745; b) D. N. Butler, R. A. Gau, P. M.
Tepperman, R. N. Warrener, ibid. 1996, 37, 2825.
[lo] R. N. Warrener, A. B. B. Ferreira. E. R. T. Tiekink, Tetrahedron Lett. 1996,37,
2161.
1111 T Mitsudo, K. Kokurya, T. Shinsugi, Y Nakagawa, Y. Watanabe, Y Takegami,
J. Org. Chem. 1979, 44, 4492.
[I21 The monoadduct can be isolated when less DADAF is employed and added in
one portion.
(131 All new compounds werecharacterized by spectroscopic techniques ('H NMR,
'3C NMR, IR) and the molecular formula established by nlicroanalysis or
mass spectrometry (see Table 1).
[I41 A. B. B. Ferreira, R. N. Warrener, unpublished results.
[I51 C. D. Smith. J. Am. Chem. Soc. 1966, 88, 4273.
[I61 M. J. Ridd, D. J. Gakowski, G. E. Sneddon, F. R. Keene, J. Chrm. Soc. Dalrun
Trans. 1992, 1949.
Angew. Chem. h t . Ed. Engl. 1996. 35, N o . 21
0 VCH
[I71 [{Ru(bpy),),(p-6)](PF6),:: yicld 82%; E.,
(metal-ligand charge transfer,
MLCT) = 448 nm (8 = 25300m0l-'drn'cin~~), CH,CN solution; E,,,
(Ru"'/Ru") = +1.04 V (vs. AgiAg', 0.1 M [(C,H,),N]CIO, in CH,CN, Pt
(MLCT) =
working electrode). [{Ru(bpy)z}z(p-9)](PF,),: yield 88 %;
448 nm ( E = 2 6 1 0 0 m o l ~ ' d m 3 c m ~ ' ) , CH,CN solution; E , c 2 (Ru"'/
Ru") = 0.97 V (vs. AgiAg', 0.1 M [(C,H,),N]CIO, in CH,CN, Pt working
yield 92%; i,,
(MLCT)
,,,= 450 nm
electrode). [{Ru(bpy),},(~-ll)J(PF~)~:
(i: = 31 400 mol 'dm3cm-'), CH3CN solution; E,,, (Ru"'/Ru") = +1.06V
(vs. Ag/Ag+, 0.1 M [(C,H,),N]CIO, in CH,CN, Pt working electrode).
[18] L. De Cola, V. Balzani. F. Barigelletti, L. Flamigni, P. Bclser, S. Bernhard, R e d .
Truv. Chim. Pays-Bas 1995, (14, 534.
1191 V. Balzani, F. Scandola, Supramolecular PhotnchemisfrJ; Ellis Horwood,
Chichester. 1991.
+
Highly Diastereoselective Synthesis and
Epoxidation of Chiral
1,2-DihydronaphthaIenes**
Torsten Linker,* Karl Peters, Eva-Maria Peters, and
Frank Rebien
Epoxidations are one of the most important methods for the
formation of carbon-oxygen bonds."' Catalytic enantioselective processes, which have been studied particularly intensively,
were first developed for allylic alcohols[21and have been extended to unfunctionalized olefins in the last few years.[31The
diastereoselective epoxidation of chiral alkenes is also very important with regard to the directing effect of various functional
groups.[41Although epoxidations of monocyclic alkenes have
attracted the most attention,['] the analogous reactions of chiral
1,2-dihydronaphthalenes have not been investigated in detail.[']
This is surprising, since achiral dihydronaphthalenes and structurally related chromenes are prime substrates for asymmetric
epoxidation~.[~I
We were interested in the synthesis and epoxidation of chiral 1,2-dihydronaphthalenes in the context of the
synthesis of podophyllotoxin analogues.r71
Oxazolines (dihydrooxazoles) 2, which are easily accessible
starting from 2-naphthoic acid (l),have proven themselves to
be good precursors for 1,2-dihydronaphthalene~~*~
(Scheme 1).
The nucleophilic addition of phenyllithium occurs with high
regioselectivity at the I-position and the trapping of the azaenolate intermediate with trifluoroacetic acid (TFA) gives the salt
rac-3 in good yield. The use of TFA has been shown to be
especially important here, since with other proton sources isomerization to 1,4-dihydronaphthalenes occurs. The exclusive
formation of the trans product is due to rapid and complete
epimerization at the 2-position and is in accordance with addiTo examine the influence of
tions to l-naphthyloxazolines.[8b1
different substituents on the stereoselectivity of the epoxidations, the salt rac-3 was transformed into the derivatives rac-4
(Scheme 1).
The oxidations were first performed with m-chloroperbenzoic
acid (MCPBA), which smoothly led to the epoxides rac-5
(Scheme 2; Table 1, entries 1-3). The yields could be improved
["I Dr. T. Linker, DipLChem. F. Rebien
lnstitut fur Organische Chemie der Universitat
Am Hubland, D-97074 Wurzburg (Germany)
Fax: Int. code +(931)888-4606
e-mail: linker~~cliemie.uni-wuerzb~~r~.de
Dr. K. Peters, E:M. Peters
Max-Planck-Institut fur Festkorperforschung, Stuttgart (Germany)
[**I This work was generously supported by the Deutsche Forschungsgemeinschaft
(Li 556/2-1, Li 556/3-I) and the Universitatsbund Wiirzburg. We thank Prof.
W. Adam for his continuous encouragement.
Verlagsgesellschaft mhH, 0-69451 Weinheim, 1996
0570-0833~96/352/-24~~7
$f5.00+ .2SjO
2487
COMMUNICATIONS
1. SOCIZ
2. NUB.
HzN
1. PhLi. -78 "C
3. SOClp
2 . F3CCOzH (TFA)
c
78%
a5%
1
rac4b
irrespective of the substituents R. From this point of view, the
observed selectivities are surprisingly high, since sterically controlled epoxidations previously reported proceed with only
moderate diastereomeric e x c e s ~ e s .d,[ 6b1
~ ~Apparently,
~
the preferred conformation of 1,2-dihydronaphthalene~[~']
is responsible for the high stereoselectivities. In AM1 calculations['z1we
found that in the most favorable rotamer of ruc-4 the phenyl
group is orthogonal to the plane of the dihydronaphthalene.
Consequently the steric requirements of this substituent is particularly large and the bottom face of the dihydronaphthalene is
effectively shielded (Scheme 3). The high-field shift of 8-H,
which is due to the induced magnetic field of the phenyl group,
is also in accordance with these calculations.
Ph
Scheme 1. Synthesis of the clnral 1,2-dihydronaphthalenesr o c 4
a
oxidant (1 1 equiv)
0)
CHzClz, 0 "C
R
rac-4
rac-4
rac-6
Ph
Ph
%\
rac-5c
Scheme 2 Oxidation of rac-4 with MCPBA and with DMD
Scheme 3. Preferred conformation of the 1,2-dihydronaphthalenes rac-4 and
crystal structure of ruc-5c.
Table 1 Epoxidation of 1.2-dihydronaphthalcnes rat-4
Entry Substrate
R
Oxidant
ds [a]
Yield [b]
rar-5
rac-6
1
2
3
4
5
6
7
8
CH,OH
CO,H
C0,Me
COzMe
CH,OH
CO,H
CO,Me
C0,Me
MCPBA
MCPBA
MCPBA
DMD
DMD
DMD
DMD
DMD[d]
>95
295
>95
>95
89
82 [c]
94
-
>95
>95
>95
>95
94
89 [c]
98
26
r.ac-4a
rue-4b
rac-4C
rac-4c
rac-4a
rac-4b
rar-4c
,.uc-4c
-
76
-
67
~~
[a] Diastereoselzctivities (ds, in %) determined froin 'H NMR spectra (250 MHz)
of the crudc product. [b] Yields (in %) of isolated product after crystallization or
column chromatography. [c] Isolated as the ester after reaction with diazomethane.
[d] Water and perchloric acid added.
by using dimethyldioxirane (DMD) as oxidant, which allows
epoxidations to be conducted under milder conditions.['l The
surprising formation of the diol rac-6c in the reaction of the
ester ruc-4c (entry 4) is due to acid-catalyzed opening of the
epoxide in the presence of traces of water. By using dirnethyldioxirane (DMD), which was synthesized under anhydrous
the desired epoxides rac-5 could be successfully
prepared in excellent yields (entries 5-7). The postulated acidcatalyzed epoxide opening was supported by a control experiment in the presence of water (entry 8).
Interestingly, only one diastereomer was formed in all reactions, regardless of the oxidant and the substituents R. The
assignment of the relative configurations of the epoxides rue-5
was not possible from the NMR data; however, the signals of
1-H to 4-H of the ring-opened product rac-6c had a characteristic coupling pattern, which confirmed the assigned configuration. The structure of epoxide rac-5c was assigned unequivocally by X-ray structure analysis.[lol
The oxidant attacks cis to the substituents R in all reactions.
However, a syn-directing effect of the hydroxy groups,[4, b1
which has often been observed previously, can be excluded for
the 1,2-dihydronaphthalenes investigated, since the homoallylic
alcohol rae-4a and the ester rac-4c show the same stereoselectivity. Rather, it is the phenyl group that controls the reaction,
2488
0 VCH
Vcdngsgesdlsthoft m h H , 0-69451 Weinheim, I996
In summary, the reaction sequence Meyers oxazoline synthesis, nucleophilic addition of phenyllithium, and epoxidation,
starting from 2-naphthoic acid (I), gives easy access to the
diastereomerically pure epoxides vac-5. The selectivities of the
reactions are strongly controlled by the steric requirements of
the phenyl group, whereas polar substituents have no influence
on the epoxidations. As 1,2-dihydronaphthalenes can be prepared enantioselectively,[sl this new epoxidation protocol may
find application in the synthesis of optically active podophyllotoxin analogues.
Experimental Procedure
Oxazoline 2 [Xb] (22.53 g, 100mmol) was dissolved in anhydrous THF (180mL)
under argon at - 40 "C. To this was added dropwise a solution of PhLi in hexane/diethyl ether 7/3 (2.06 M, 60 mL, 124 mmol). The reaction mixture was stirred for 3 h
at this temperature, then a mixture of TFA (30 mL, 3x9 mmol) and THF (20 mL )
was addcd. After 10 min the reaction mixture was poured into a saturated ainmonium chloride solution (200 mL) and extracted with dietliyl ether (3 x 80 mL). The
combined organic phases were dried over Na,SO, and crystallized at 0 'C, directly
yielding the salt rac-3 (29.6 g, 68%; m.p. 1555156°C). Upon concentration of the
motherliquorafurthercrop ofthe product wasobtained(7.4 g, 17%). Under argon
atmosphere a solution of ruc-3 (13.06 g, 30 mmol) in 3 N HCI (200 mL) was heated
at reflux for 7.5 h, cooled, and then extracted with ethyl acetate (4 x 50 mL). The
combined organic phases were dried over Na,SO, and then concentrated under
vacuum. Filtration through a short column of silica gel (hexanejethyl acetate 614)
yielded the acid rac-4b in the form of white crystals (7.35g, 98%; m.p.
121-122 T).To a solution of rar-4b (2.5 g, 10 mmol) in dichloromethane (50 mL)
at 0 'C was added a solution of diazomethane in diethyl ether until the yellow color
persisted. After 12 h a t 20 "C the solution was concentrated and filtered over a short
column of silica gel (hexanelethyl acetate 8/21to yield the ester rac-4c (2.62 g, 99 %)
Anal. calcd. for C,,H,,O,: C 81.79, H 6.10; found: C 81.47, H 5.97; ' H N M R
(200 MHz, CDCI,): 6 = 3.63 (s. 3H, OMe), 3.70 (ddd, J = 8.6, 4.3, 2.1 Hz. 1 H.
2-H),4.64(d.J=8.6H~,lH.I-H).5.94(dd,J=9.6,4.3Hz,lH,3-H),6.66(dd,
J = 9.6. 2.1 Hz, l H , 4-H), 6.89 (d. J =7.2Hz. 1 H, 8-H), 7.12-7.32 (m, XH, aromat. H); I3C NMR (50 MHz, CDCI,): 6 = 45.8, 48.5, (2 d, C-1, C-2), 52.1 (q,
CO,Me), 123.6, 126.5, 126.8, 127.0, 128.0, 128.3. 128.5, 128.6.129.1 (9d, C-3, C-4.
C-5, C-6, C-7. C-8, C-Ph), 132.4, 136.2. 142.8 (3 s. C-9, C-10, C-Ph), 173.6 (s,
CO,Me).
The ester r a c - 4 ~(2.12 g, 8.02 mmol) was dissolved in anhydrous dichloromethane
(120 mL). A solution ofDMD [9c] in acetone (0.06 ~.15GmL, 1.1 eqmv) was added
dropwise to this solution at 0 "C over 30 min. After 2 h at 0 "C the reaction mixture
was conceiilrated directly on a rorary evaporator. Crystallization from diethyl
ether gave the epoxide rac-5c as white needles (2.2g, 98%; m.p. 97-9X'C).
Anal. calcd. for C,,H,,O,: C 77.12, H 5.75; found: C 76.86, H 5.63; ' H N M R
OS70-0833/9613521-2488S 15.00+ .2S/U
Annm. Chem. In[. Ed. Ennl. 1996, 35, No. 21
COMMUNICATIONS
(200 MHz, CDC1,): 6 = 3.20 (dd, J = 12.0, 0.8 Hz, 1 H, 3-H), 3.61 (s, 3H, OMe),
3.96 (dd, J = 4 . 3 , 0.8H2, l H , 2-H), 4.06 (d, J = 4 . 3 H z , I H , 1-H), 4.33 (d,
J=12.0Hz, I H , 4-H), 6.56 (dd, J=7.4, I.OHz, l H , 5-H), 7.12-7.49 (m, SH,
aromat. H); ’’C NMR (50 MHz, CDCI,): 5 = 43.1, 48.1, (2d, (2-3, c-4), 52.2 (q,
CO,Me), 53.0, 55.6 (2d. C-1, C-2), 126.5, 127.3, 128.4, 128.7, 128.8, 129.7, 129.8
(7 d, C-5, C-6, C-7, C-8, C-Ph), 131.4, 139.1, 140.1 (3 S, C-9, C-10, C-Ph), 172.7 (s,
C0,Me).
Received: June 7, 1996 [Z9196IE]
German version: Angew. Chem. 1996, 108, 2662-2664
Keywords: asymmetric syntheses * dihydrooxazoles
tions
*
naphthalene derivatives
*
*
epoxida-
synthetic methods
[I] Reviews: a) G. Berti, Top. Stereochem. 1973, 7, 93-251; b) H. Mimoun,
Angew. Chem. 1982,94,750-766; Angew. Chem. Int. Ed. Engl. 1982,21.734750; c) A. S. Rao, S . K. Paknikar, J. G. Kirtane, Tetrahedron 1983,39, 23232367; d) V. Schurig, F. Betschinger, Chem. Rev. 1992,92,873-888; e) P. Besse,
H. Veschambre, Tetrahedron 1994, SO, 8885-8927; f) S. PedragosaMoreau, A. Archelas. R. Furstoss, Bull. Soc. Chim. Fr. 1995, 132, 769-800.
[2] a) T. Katsuki, K. B. Sharpless, J. Am. Chrm. Soc. 1980, 102, 5974-5976; b)
R. A. Johnson, K. B. Sharpless in Comprehensive Organic Synthesis, Vol. 7
(Eds.: B. M. Trost, I. Fleming, S. V. Ley), Pergamon, New York, 1991,
p. 389-436; c) R. A. Johnson, K. B. Sharpless in Catalytic Asymmefrrc Synihe
sis (Ed.: 1. Ojima), VCH, Weinheim, 1993, pp. 103-158.
[3] a) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, J. Am. Chem. Soc.
1990, ff2,2801-2803; b) R. hie, K. Noda, Y Ito, N. Matsumoto, T. Katsuki,
Tetrahedron Lefl. 1990, 31, 7345-7348; c) E. N. Jacobsen in Catalytic Asymmetric Synthesis (Ed.: I. Ojima), VCH, Weinheim, 1993, pp. 159-202; d) T.
Katsuki, Coord. Chem. Rev. 1995, f40,189-214.
[4] Review: A. H. Hoveyda, D. A. Evans, G. C. Fu, Chem. Rev. 1993,93, 13071370.
[5] a) W Adam, A. K. Smerz, Tetrahedron 1995, Sf, 13039-13044; b) R. J. Linderman, R. J. Claassen, 11, F. Viviani, Tetrahedron Lett. 1995,36, 6611-6614;
c) R. W. Murray, M. Singh, B. L. Williams, H. M. Moncrieff, J. Org. Chem.
1996,61,1830-1841; d) E. Vedejs, W. H. Dent, 111, J. T. Kendall, P. A. Oliver,
J. Am. Cliem. SOC.1996,118, 3556-3567.
[6] A few exceptions: a) R. W. Irvine, R. A. Russell, R. N. Warrener, Tetrahedron
Left. 1985, 26, 6117-6120; b) M. J. Martinelli, B. C. Peterson, V. V. Khau,
D. R. Hutchison, M. R. Leanna, J. E. Audia, J. J. Droste, Y-D. Wu, K. N.
Houk, J. Org. Chem. 1994, S9, 2204-2210; c) F. Orsini, F. Pelizzoni, Tetrahedron: Asymmetry 1996, 7, 1033-1040.
171 Review: R. S. Ward, Synthesis 1992, 719-730.
[8] a) M. Reumann, A. I. Meyers, Tetrahedron 1985,41,837-860; b)A. I. Meyers,
K. A. Lutomski, D. Laucher, ihid. 1988.44, 3107-3118; c) G. T. Gant, A. I.
Meyers, &id. 1994, 50, 2297-2360.
[9] a) W. Adam, R. Curci, J. 0. Edwards, Acc. Chem. Res. 1989,22,205-211; b)
R. W. Murray, Chem. Rev. 1989, 89, 1187-1201; c) W. Adam, L. Hadjiarapoglou, J. Bialas, Chem. Ber. 1991, 124, 2377; d) R. Curci, A. Dinoi, M. F.
Rubino, Pure Appl. Chem. 1995,67, 811-822.
[lo] Crystal data for rac-5c: C,,H,,O,, Siemens P4 diffractometer, monoclinic,
P2,/n, a = 1615.4(7), b = 548.4(3), c = 1646.3(6) pm,
= 96.16(2)”,
V = 1450(1) x lo6 pm3, psalsd
=1.284 gem-,, 20,., = 55”, Z = 4, Mo,, radiation, 1 =71.073 pm, w-scan, p = 0.09 mm-’, T = 293 K, structure solved by
direct methods, 3351 measured reflections, 2945 unique reflections, of which
1792 had F > 3a(F), FJparameter ratio = 9.43, R = 0.066, R, = 0.065, refined versus 1 FI. Residual electron density of the difference-Fourier map:
max = 0.22, min = - 0.35 e k 3 . Program: SHELXTL-PLUS. Further details of the X-ray structure investigation may be obtained from the Fachinformationszentmm Karlsruhe, D-76344 Eggenstein-Leopoldshafen (Germany),
under the depository number CSD-405437.
[ l l ] P. W Rabideau, A. Sygula, The Conjormational Analysis of Cyclohexenes, Cyclohexadienes, and Related Hydroaromatic Compounds, VCH, Weinheim, 1989,
pp. 77-81.
[12] G. Rauhut, J. Chandrasekhar, A. Alex, T. Steinke, T. Clark, VAMP 5.0, Universitat Erlangen. 1993.
Catalytic Activation of C-H Bonds in Aromatic
Hydrocarbons, Ethene, and Methane by
the Naphthalene/Sodium System in
Tetrahydrofuran**
Siegbert Rummel,* Margarita A. Ilatovskaya,
Evgeny I. MYSOV,
Vladimir S. Lenenko,
Helmuth Langguth, and Vladimir B. Shur
Radical anions formed from naphthalene and alkali metals
are classical objects of chemical research, frequently used because they can efficiently transfer electrons to organic and inorganic substrates. They have achieved particular importance as
catalysts for the polymerization of 1,3-dienes and some monoenes, in which “living” polymers are formed.
One of the characteristic reactions of the radical anion adducts
of alkali metal ions with naphthalene and other aromatic hydrocarbons is the rapid and reversible electron transfer between the
anionic species and the hydrocarbon [Eq. (a)]. Analogous elecArH‘-
+ ArH
ArH
F=??
+ ArH*-
(a)
tron transfer processes can also take place between the radical
anions themselves [Eq. (b)]. Although there are already numer2 ArH’-
ArH
+ ArHZ-
(b)
ous publications on electron transfer of this type,“] to the best
of our knowledge no one has hitherto investigated the reversible
hydrogen transfer reactions between C-H bonds of hydrocarbons in these and similar systems. To clarify this question we
chose the naphthalene/sodium system, which is formed by addition of sodium to an equimolar mixture of [D,]naphthalene and
[DJnaphthalene in [D,]THF, and investigated whether hydrogen isotope exchange takes place between the naphthalene rings.
The experiments were carried out under argon with careful
exclusion of air and moisture. The molar ratio of sodium to
naphthalene was 0.5: 1 , l : 1, and 2: 1. In the last case some of the
sodium remained undissolved because of the excess employed.
After removal of the solvent by distillation in vacuum at 20 “C
we analyzed the sublimed naphthalene by mass spectrometry.[2*31In addition to the H/D exchange in naphthalene we
investigated whether analogous isotope exchange processes take
place with other hydrocarbons, for example, with benzene,
toluene, ethene, and methane.13]
In our earlier work we had foundr4,51 that adducts of active
carbon with metallic potassium, and also graphite-potassium
lamellar compounds, are able to activate C-H bonds in various
hydrocarbons and to catalyze the hydrogen isotope exchange at
room temperature. Herein we report that analogous H/D exchange reactions take place in the naphthalene/sodium system
in T H E
In a typical experiment, metallic sodium and [D,]THF were
added under argon to a 1 : I mixture of [Do]naphthalene and
[*] Dr. habit. S. Rummel, Dr. H. Langguth
Institut fur Oberfliichenmodifizierung e. V.
Permoserstrasse 15, D-04303 Leipzig (Germany)
Fax: Int. code +(341)235-2584
e-mail : rummel@,serveri.rz.uni-leipzig.de
Dr. M. A. Ilatovskaya, Dr. E. I. Mysov, Dr. V. S. Lenenko,
Prof. Dr. V. B. Shur
A. N. Nesmayanov Institute of Organo-Element Compounds of the Russian
Academy of Sciences
Vavilov Street 28, 117813 Moscow (Russia)
[**I This work was supported by the Buudesministerium fur Forschung und Technologie (BMFT) , Bonn.
Angew. Chem. I n f . Ed. Engl. 1996, 35, No. 21
0 VCH Verlaggesellschaft mbH. 0-69451 Wemheim, 1996
0570-0833/961352f-2489$ f5.00+ ,2510
2489
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chiral, diastereoselective, synthesis, epoxidation, dihydronaphthalenes, highly
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