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Synthesis and Interconversion of New (CH)14 Isomers.

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2 + 4 rearrangement, the 2-norbornyl cation returned mainly to the oxygen atom of the p-toluenesulfinate ion from
which it dissociated. Furthermore, the results in Table 1
show that C1 and C2 of the 2-norbornyl cation are not
equivalent in ion pair recombination. For 5 Aa the recombination path c) was favored by a factor 2-3 over d). This
finding was supported by experiments with 5Ba (no. 7 and 8
in Table 1): recombination b) was not measurable; the ratio
of paths a), d), and c) was about 8:2:1. The complementary
results for 5Aa and 5Ba preclude the predominant formation of one diastereomer on recombination of 6.[211Instead
thep-toluenesulfinate ion returned, after the exchange of the
oxygen atom, preferentially to the carbon atom of the 2-norbornyl cation from which it dissociated (C2). A corresponding preference must also be valid before oxygen exchange.
The symmetric, bridged structure of the 2-norbornyl
cation has been established by several spectroscopic and theoretical studies.[221As a rule, nucleophiles do not discriminate between C1 and C2. Exceptions are known, however:
~ "the
for example, the addition of HX to n o r b ~ r n e n e [ ~or
decomposition of 2-norbornanediazonium
the norbornyl cation is trapped in unsymmetric form. The
dependence of such processes on the solvent[241suggests the
intervention of ion pairs in which the counterion is found
closer to C2 than to C1 depending on the history of its
formation. In contrast to this interpretation, no regioselective recombination has been observed on heterolysis of 2norbornyl derivatives.[251Our results close this gap : they
confirm that the close-range order in ion pairs can lead to
discrimination between C1 and C2 of the 2-norbornyl cation.
Received: February 5, 1991 [Z4428 IE]
German version: Angew. Chem. 103 (1991) 989
CAS Registry numbers:
2A, 134334-51-3;4A(I80), 134334-54-6;SAa, 134334-52-4;5Bb,134334-53-5;
2-norpinol, 38102-34-0; p-toluenesulfinyl chloride, 10439-23-3; exo-2-norbornanol, 497-37-0.
[I] Summaries: a) M. Szwarc: Ions andlon Pairs in Organic Reactions, Wiley,
New York 1972; b) J. M. Harris, Prog. Phys. Org. Chem. 11 (1974) 89;
c) T. E. Hogen-Esch, Adv. Phys. Org. Chem. f5 (1977) 153; d) H. Kessler,
M. Feigel, Acc. Chem. Res. 15 (1982) 2.
[2] S. Winstein, E. Clippinger, A. H. Fainberg, R. Heck, G. C. Robinson, J.
Am. Chem. SOC.78 (1956) 328.
[3] a) H. L. Goering, Rec. Chem. Prog. 21 (1960) 109; b) H. L. Goering, J. T.
Doi, J. Am. Chem. SOC.82 (1960) 5850; c) H. L. Goering, J. L. Levy, ibid.
86 (1964) 120; d) H. L. Goering, J. T. Doi, K. D. McMichael, ibid.
86(1964) 1951; e) H. L. Goering, R. G. Briody, G. Sandrock, ibid. 92
(1970) 7401; f) H. L. Goering, H. Hopf, ibid. 93 (1971) 1224; g) H. L.
Goering, G. S. Koerner, E. C. Linsay, ibid. 93 (1971) 1230.
[4] a)S. Winstein, P. E. Klinedinst, G. C. Robinson, J. Am. Chem. SOC.832
(1961) 885; b) S. Winstein, P. E. Klinedinst, E. Clippinger, ibid. 83 (1961)
4986; c) A. F. Diaz, I. Ladzins, S. Winstein, ibid. 90 (1968) 1904; d) H. L.
Goering, R. W. Thies, ibid. 90 (1968) 2967, 2968; e) H. L. Goering, B. E.
Jones, ibid. 102 (1980) 1628; f) C. Paradisi, J. F. Bunnett, ibid 103 (1981)
946; g) Y. Yukawa, H. Morisaki, K. Tsuji, S.-G. Kim, T. Ando, Tetrahedron Left. 1981,5187; h) C. Paradisi, J. F. Bunnett, J. Am. Chem. Soc. 107
(1985) 8223; i) M. Fujio, F. Sanematsu, Y. Tsuno, M. Sawada, Y. Takai,
Tetrahedron Letr. 29 (1988) 93; j) P. Dietze, M. Wojciechowski, J. Am.
Chem. SOC.112 (1990) 5240.
[5] S. Braverman in S. Patai, Z. Rappoport, C. J. M. Stirling (Ed.): The Chemisfry ofsulfones and Sulfoxides, Wiley, Chichester 1988, Chap. 13.
[6] Some ally1 and propargyl sulfinates undergo concerted [2,3]-sigmatropic
rearrangements, e.g., a) S. Braverman, Int. J. Sulfur Chem. Part C6 (1971)
149; b) S. Braverman, H. Mechoulam, Tefrahedron 30 (1974) 3883; c) S.
Braverman, D. Segev, J Am. Chem. SOC.96 (1974) 1245; d) P. A. Grieco,
D. Boxler, Synth. Commun. 5 (1975) 315; e) J. E. Baldwin, 0. W. Lever,
N. R. Tzodikov, J. Org. Chem. 4f (1976) 2312; f) K. Hiroi, R. Kitayama,
S. Sato, J. Chem. SOC.Chem. Commun. 1983,1740; Chem. Pharm. Bull. 32
(1984)2628; g) D. J. Knight, G. H. Whitham. J. G. Williams,J. Chem. Soc.
Perkin Trans. 1 1987, 2149.
[7] E. Ciuffarin, M. Isola, A. Fava, J. Am. Chem. Soc. 90 (1968) 3594.
[8] HPLC: 25 x 2.5 cm Polygosil 60-10 C,,, metbanol:water=7:3. Although
many "cuts" of the overlapping peaks were made, only the first fraction
could be obtained pure (monitored by GC). I3CNMR (CDCI,,
0 VCH VerlagsgesellschaJi nibH. W-6940 Weinheim. 1991
100.6 MHz) [p = primary, s = secondary, t = tertiary, q = quarternary
carbonatom(DEPT):6 = 21.46(p),25.16(~),26.15(~),26.45(~).33.11
33.60 (s), 40.16 (t), 79.76 (t). 125.03 (t), 129.53 (t), 142.33 (q), 142.33 (q),
142.78 (q).
[91 The structural analysis has not yet been completed; the assignment of the
diastereomers is arbitrary. Racemates were used; only one enantiomer is
shown in Scheme 1.
[lo] Prepared by a Dieis-Alder reaction from cyclopentadiene and ethynyl
p-tolyl sulfone [I I] and subsequent hydrogenation (Pd-C, ethyl acetate)
for comparison; yield 94%, m.p. 62°C.
[Ill T. J. Chow, T. H. Lin, Bull. Inst. Chem. Acad. Sin. 33 (1986) 47; Chem.
Absrr. 107 (1987) 39256.
[I21 Prepared from endo-2-norbornanol and p-toluenesulfinyl chloride (pyridine, 0 ° C 48 h, 98%) for comparison. The isomers were separated by gas
chromatography (32 m capillary column, Carbowax + KOH, 165"C), but
not on a preparative scale (HPLC). The mixture showed clearly separated
"C NMR signals for C2 of the diastereomers, 6=78.40 and 78.56.
[I 31 Prepared from exo-2-norbornanol and p-toluenesulfinyl chloride (pyridine, 28°C 48 h, 92%); separation of the diastereomers by HPLC 181. I3C
NMR(CDC1,): A: 6 = 21.49 (p), 24.24 (s), 28.08 (s), 34.99 (s), 35.40 (t),
40.87 ( s ) , 42.91 (t), 81.69 (t), 124.99 (t), 129.55 (t), 142.36 (9). 142.95 (q);
B: 6 = 21.48 (p), 24.13 (s), 28.03 (s), 34.90 ( s ) , 35.34 (t), 430.36 (s), 42.88
ft), 80.49 (t), 125.10 (t). 129.58 (t), 142.32 (4). 142.67 (4).
[I41 S. Cristol, G. D. Brindell, J. Am. Chem. SOC.76 (1954) 5699.
I151 Review: W. Kirmse, Acc. Chem. Res. 19 (1986) 36.
[16] The incorporation of " 0 was achieved by exchange between 2-norpinanone and H,180, followed by reduction (NaBH,), esterification, and
separation by HPLC [8]. The sample of 4A used contained 32% '*O.
[I71 The ester I8O atom caused a shift of A6=0.04 to higher field for the I3C
NMR signal of C2. The quantitative analysis was performed by integration of the 160-"C and '80-'3C signals (4: f 2%; 5: _+ 10% because of
the small quantities). For the method, see [4i].
[18] With increasing reaction times, the ratio of the diastereomers and the l8O
label approached an equal distribution (cf. no. 1 and 2 , 4 and 5 in Table 1);
moreover the concentration of 5 decreased as a result of rearrangement to
sulfone 7 and solvolysis (formation of 2-norbornyl formate or trifluoroacetate. Theoretically the preferences of the ion-pair recombination are
clearest at small turnovers. In practice the experimental error is then large.
We chose a compromise between these divergent requirements in our 1530% turnovers.
[I91 '80-exo-2-norbornano1 was prepared by hydroxymercuration of norbornene in H,"O/THF and treated further to give 5Aa and 5Ba [13](53.6%
[20] Preparation of [2-2H]-exo-2-norbornanol:N. H. Werstiuk, D. Dhanoa, G.
Timmins, Can. J. Chem. 61 (1983) 2403. 'HNMR (CHCI,, 61.4MHz):
['HI-SA: 6 = 4.28, 2.26; [*H]-5B: 6 = 4.28, 2.48.
[21] The solvolysis of a 1:1 mixture of 5A and 5B also gave no indication of
diastereoselective recombination. No significant change in the 5 A 5 B ratio
was observed during the decrease in concentration of 5.
[22] More recent summaries: a) D. Lenoir, Y. Apeloig, D. Arad, P. von R.
Schleyer, J. Org. Chem. 53 (1988) 312; b) G. A. Olah, G. K. S. Prakash,
R. E. Williams, L. D. Field, K. Wade: Hypercarbon Chemistry, Wiley,
New York 1987, p. 157; c) P. Vogel: Carbocarion Chemistry, Elsevier, Amsterdam 1985, p. 281.
[23] Review: a) H. C. Brown: The Nonclassicallon Problem (withcomments by
P. von R. Schleyer), Plenum, New York 1977, p. 225; b) [23a], p. 219.
[24] a) Dediazotization: W. Kirmse, R. Siegfried, J. Am. Chem. SOC.105 (1983)
950; b) HX addition: W. Kirmse, S. Brandt, Chem. Ber. 117 (1983) 2524.
[25] a) E. J. Corey, J. Casanova, Jr., P. A. Vatakencherry, R. Winter, J. Am.
Chem. SOC.85 (1963) 169; b) S. G. Smith, J. P. Petrovich,J. Org. Chem. 30
(1965) 2882; c) L. A. Spurlock, T. E. Parks, J Am. Chem. Soc. 92 (1970)
Synthesis and Interconversion of New (CH),,
By Wolf-Dieter Fessner,* and Maria Rodriguez
Dedicated to Professor Horst Prinzbach
on the occasion of his 60th birthday
The homologous series of (CH),, hydrocarbons-valence
isomers of [2n]annulenes+ontinue to be the subject of the
Dr. W-D. Fessner, M. Rodriguez
Institut fur Organische Chemie und Biochemie der Universitat
Albertstrasse 21, W-7800 Freiburg (FRG)
[**I This work was supported by the Fonds der Chemiscben Industrie. We
thank BASF AG for a gift of cyclooctatetraene.
Angew. Chem. In!. Ed. Engl. 30 (1991) No. 8
most varied studies because of their theoretical importance
and their unusual propensity towards photochemical, thermal, and catalytic conversions. In connection with studies to
differentiate between through-space (e.g. in isodrines A['] or
homohypostrophenes D['1) and through-bond electronic interactions (e.g. in triblattenes Br3'or hemfpagodanes CL4]),
Me@ / MeCN
5 YY
we were interested in the properties of the polycycle 1, a new
unsaturated member of the (CH),, family, and in its potential as precursor for the C,,-symmetric (CH),, triene E. Here
we report on two high-yield routes to 1, starting from the
known COT-p-benzoquinone cycloadduct 2, and on first
results for its thermal and photochemical transformations
into further (CH),, isomers.
7 a R=Mes
7 b R=Ta
We chose the structurally related diketone 3 as starting
material for the cyclobutene-bridged diene 1, based on the
analogous syntheses of hypostrophene and C,,-symmetric
homologues D.[',
Compound 3 is obtained efficiently by
intramolecular [2 + 21 photocycloaddition from the tetracycle 2, which is in turn accessible through the Diels-Alder
reaction of COT and p-benzoquinone (literature yield"]:
25 %); by improving the [4 + 21 cycloaddition to a 65 -70 %
yield (sealed tube, THF, 24h at 125°C; or diglyme, 24h at
140 "C), the valuable diene component could be used effectively. In contrast to the known synthesis routes for dienes of
type D-obtained mainly through an acid catalyzed skeletal
isomerization with participation by the photochemically
formed four-membered ring['* 61-the reactivity of the cyclobutene unit required a modified strategy. Therefore, we selected as primary target the exo,exo-diiodide 8, which appeared accessible through nucleophilic substitution from
suitable precursors and able to undergo a subsequent 1,4
elimination to 1.
Whereas the reduction of diketone 3 with NaBH, stops at
the hemiacetal (4) stage, with LiAIH, it proceeds smoothly
5 3
Angew. Chem. Inl. Ed. Engl. 30 (1991) No. 8
to form a sparingly soluble diol (70%, m.p. 202°C). The
simplicity of the NMR spectra and the coupling pattern suggested high molecular symmetry and an endo,endo configuration for the alcohol functions in 5, which was confirmed by
transformation into the acetonide 6 (76 YO,m.p. 108 "C). As
the bis(mesy1) ester 7a (91 %, m.p. 102 "C) proved to be unstable on storage, we used the bis(tosy1ate) 7 b (86Y0, m.p.
134°C) for reaction with Nal. Although the workup yielded
the desired inversely configurated compound 8, the amounts
were not satisfactory (18 YO,m.p. 156"C), and the ether 9 was
the major component (36%, m.p. 92°C). The latter is probably formed by a competitive attack of the nucleophile at the
sulfonate and subsequent intramolecular substitution. In an
attempt to prepare the diiodide 8 from the bis(sily1) ether 10
by treatment with iodotrimethylsilane, only 9 was isolated
instead (65%), which must be attributed on one hand to
steric hindrance and on the other to anchimeric stabilization
of electrophilic intermediates.
After the treatment of 8 with Na/K alloy in ether, the 'H
NMR spectrum of the crude product showed signals due to
olefinic compounds. Separation of the components into the
heptacycle 12 (9%) and the trienes 11 (5%) and 1 (74%,
m.p. 88°C) was achieved by chromatography on AgN0,impregnated aluminum oxide with pentane/ether mixtures.[']
The ratio of the trienes, which can be attributed to competing 1,4 cleavage of the comparably oriented relay bonds a
and b, may be interpreted as a reflection of the relative bond
strain. The formation of a pentaprismane homologue (12),
however, is without precedent;['] one can only speculate on
the character of the homo- or heterolytic impulse which triggers the transannular bond formation.
The unsatisfactory total yield of 1 and the effort required
for its chromatographic separation made us look for an alternative synthesis. And indeed, on treatment with Zn/
H O A C the
~ ~diketone
~ ~ ~ 3 forms the enone 13 surprisingly
8 - Na-K
Verlagsgesellsehafi mbH. W-6940 Weinheim, 1991
smoothly (59 YO,m.p. 87 0C[81;in addition 27 % of 4)without attack on the cyclobutene unit. Esterification of the corresponding enolate to afford the phosphate 14 (91 YO,oil)
and its subsequent reduction with lithium in ammonia yields
exclusively the triene 1 (75 YO)in economical total yield.
The reactions of 1 are noteworthy. Moreover, they serve
to confirm its structure: Triplet-sensitized photolysis (acetone, Hg medium pressure lamp, Duran filter) initiates
[2 21 cycloaddition to 12 typical for dienes D, while heating
in solution to 2 80°C induces a quantitative, regiospecific
[3,3] shift to 11. No indication is found in the 'H NMR
spectrum for the participation of isomer 15 (I1%, Fig. 1) in
AH,*: 107 2 kcal mol-'
Angew. Chem. 100 (1988) 1140-1143; Angew. Chem. I n f . Ed. Engl. 27
(1988) 1103-1106.
[4] G. Sedelmeier, W.-D. Fessner, R. Pinkos, C. Grund, B. A. R. C. Murty, D.
Hunkler, G. Rihs, H. Fritz, C. Kriiger, H. Prinzbach, Chem. Ber. 119
(1986) 342-3472,
[5] G. R. Underwood, B. Ramamoorthy, Chem. Commun. 1970,12-13; Erratum: ibid. 1971, 600.
[6] a) E. C. Smith, J. C. Barborak, J. Org. Chem. 41 (1976) 1433-1437; b)
A. P. Marchand, T.-C. Chou, J. D. Ekstrand, D. van der Helm, ibid. 41
(1976) 1438-1444;c)P. E.Eaton, L. Cassar,R. A.Hudson, D. R.Hwang,
ibid. 41 (1976) 1445-1448; d) D. C. Dong, J. T. Edward, Can. J. Chem. 58
(1980) 1324- 1326.
[7] J. C. Barborak, D. Khoury, W. F. Maier, P. von R. Schleyer, E. C. Smith,
W. F. Smith, C. Wyrick, J. Org. Chem. 44 (1979) 4761-4766.
[8] Selected 'H NMR data (250 MHz, CDCI,): pentacyclo['~1*,03,6.07,11]tetradeca-4,9,13-triene
1: 6 = 2.19 (m, 2H), 2.25 (m. 2H), 2.64 (m.
2H), 2.99 (m, 2H), 6.07 (dd, 2H), 6.16 (dd, 2H), 6.32 (s, 2H). (1a,2a,3a,6a,7P,1OP,l1 cc,14a)-Pentacyclo[]tetradeca4,8,12-triene 11: 6 = 2.94 (m, 4 H), 3.14 (s, 2 H), 4.65 (m, 2 H), 5.32 (d, 2 H),]5.71 (d, 2 H), 6.05 (s, 2H). - Heptacyclo['.03~6.04~
tetradec-11-ene 12: 6 = 2.01 (m, 2H). 2.78-2.90 (m, 6H), 3.03 (m,2H),]3.10 (m, 2H), 6.30 (s, 2H). - (~)-unti-Pentacyclo[
tetradeca-4,13-dien-9-one13: 6 = 1.92 (dd, 1 H), 2.11 (d, 1 H), 2.24-2.37
(m,2H),2.46 (m, 3H),2.66(m, 1H),2.97 (m,2H),6.17(m, IH), 6.31 (m,
1 H), 6.36 (s, 2 H).
[91 E. Wenkert, J. E. Yoder, J. Org. Chem. 35 (1970) 2986-2989.
[lo] M. Maas, M. Lutterbeck, D. Hunkler, H. Prinzbach, Tetrahedron Lett. 24
(1 983) 2143 - 2146.
[l I] As this trend persists for diverse structural variants of type D, the order of
magnitude of the error ( 2 5 kcalmol-') also implies an unsatisfactorily
balanced parameterization of the MM2 force field (N. L. Allinger, J. Am.
Chem. Soc. 99 (1977) 8127-8134) for cyclopentene compounds. W.-D.
Fessner, W. R. Roth, unpublished results.
AHto= 115 L kcal rnol-'
Fig. 1. Comparison of the calculated minimum geometries of the potential
Cope isomers of 1;heat of formation and intramolecular distances from MM2
calculations Ill].
1,2,3-Triphospha-4-silabicyclo[l.1.O]butanes from
Activated, Stable Phosphasilenes
and White Phosphorus**
By Matthias DrieJ*
an equilibrium. In contrast, attempts to induce the thermal
isomerization of the enolate of 13 or of the enol ester 14 were
dominated by unspecific decomposition.
The exclusive formation of the anti isomer 11 is in agreement with force-field calculations, which estimate an energy
higher by ca. 8 kcal mol - for the syn isomer 15 (both higher
homologous unsaturated tris-[3.2.2]-o-homoben~enes['~~)
a result of steric compression and unfavorable torsional interactions (Fig. 1). However, the heat of formation of the
experimentally less stable structural isomer 1 (dz-z = 2.651 A)
is strongly underestimated (ca. 0.8 kcal mol - lower than
which has to be ascribed in part to destabilizing z-z
interactions neglected by the computational method (MM2).
Received: January 14, 1991 [24383 IE]
Publication delayed on authors' request.
German version: Angew. Chem. 103 (1991) 985
CAS Registry numbers:
1 , 134208-60-9; 2, 86471-43-4; 3,3037-86-3; 4,134208-61-0; 5, 134208-62-1;6,
134208-63-2;7s, 134208-64-3;7b, 134208-70-1;8,134208-65-4; 9,134208-66-5;
10, 134208-67-6; 11, 134208-68-7; 12, 134237-88-0; 13, 134208-69-8; 14,
[l] a) J.-P. Melder, F. Wahl, H. Fritz, H. Prinzbach, Chimiu 41 (1987) 426428; b) H. Prinzbach, G. Sedelmeier, H.-D. Martin, Angew. Chem. 89
(1977) 111-112; Angew. Chem. Inl. Ed. Engl. 16 (1977) 103-104.
[2] a) W-D. Fessner, G. Sedelmeier, L. Knothe, H. Prinzbach, G. Rihs, Z.-Z.
Yang, B. Kovac, E. Heilbronner, Helv. Chim. A c f a 70 (1987) 1816-1842;
b) G. Sedelmeier, H. Prinzbach, H.-D. Martin, Chimia 33 (1979) 329-332,
and references cited therein.
(31 a) W.-D. Fessner, H. Prinzbach, Tetrahedron 42 (1986) 1797-1803; b) H.
Miiller, J.-P. Melder, W.-D. Fessner, D. Hunkler, H. Fritz, H. Prinzbach,
0 VCH Verlagsgesellschaft mbH, W-6940 Wernheim, 1991
Bicyclo[l. 1 .O]butanes in which the ring-C atoms are completely replaced by silicon and/or elements of Group 15 are
interesting because of their unusual bonding."] Comparative
experimental and theoretical studies of bicyclo[l . I .O]butane
derivatives with P, (A) and Si, (B) frameworkst'] indicate
that the bonds between the bridgehead atoms are substantially weakened in the silicon skeleton, but both systems
possess remarkable ring dynamics.
Recently the first bicyclo[l .I .O]butane with a Si,P, framework, a 1,3-diphospha-2,4-disilabicyclo[l. I .O]butanederiva~ ~ P-P bond in C has a diradical
tive (C) was r e ~ 0 r t e d . lThe
nature; this system therefore resembles compounds of type A
more than type B.14] Type C compounds were prepared by
treatment of tetraorganodisilenes (R,Si=SiR,) with white
p h o ~ p h o r u sand
~ ~ ]lately also by dehydrogenation of 2,2,4,4tetraorgano-l,3-diph0spha-2,4-disiletanes.~~~
The smooth
access to C from disilenes and P, raised the question whether
this synthesis principle would not also be effective for the as
yet unknown SIP, systems, D. Kinetically stable phosphasilenes (R,Si=PR) which must be thermally stable yet reactive enough to react with P, are required as starting compounds. The only phosphasilene stable at 60°C which could
be obtained pure (spectroscopic criteria), Is(tBu)Si=PMes*t61
(Is = 2,4,6-triisopropylphenyl (isityl), Mes* = 2,4,6-tri-tert[*I Dr. M. DrieD
Anorganisch-chemisches Institut der Universitat
Im Neuenheimer Feld 270, W-6900 Heidelberg (FRG)
[**I This work was supported by the Fonds der Chemischen Industrie and the
Deutsche Forschungsgemeinschaft.
0570-0833191lO808-10223 3.50+ ,2510
Angew. Chem. I n f . Ed. Engl. 30 (1991) No. 8
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