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Extensions of the Tricyclooctanone Concept. A General Principle for the Synthesis of Linearly and Angularly Annelated Triquinanes

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whether the monoanion 6b, obtained by the first alkylation
in the 1-position would tend to react via C-alkylation in
position 3 (product 2), by 0-alkylation (products 7 and 8),
or-after proton migration-by C-alkylation in position 1
(product 9).
We investigated this reaction as a function of the chain
length of the alkylating agent, the halide leaving group,
and the ion-pair structure:[’’
- 1,2-dibromoethane reacts with the dianion of 2-indanone to give solely the spiroannelated product 9a; 1,3dibromopropane affords a mixture of 2b and 8b;I6]1,4dibromobutane gives a complex mixture of products,
which cannot be separated, but in which, according to
NMR, no enol ether is present.
- The ratio of C,C- to C,O-alkylation products (2b/8b) increases in going from dibromo- to diiodopropane (a
“softer” electrophile) from 2 : 1 to 5 :1.
- This product ratio, observed in T H F solution, is increased by addition of hexane and reduced by addition
of hexamethylphosphoric triamide;’” the product ratio
2b/8b is 20 : 1 if THFIhexane (6 : 4) is used as solvent.
Even in dilute solution, considerable amounts of oligomeric products are formed; in a typical experiment (1,3dibromopropane, THF), the yield of 2b/8b is 31%. The
separation of the products is achieved by column chromatography.
The variation of the alkylating agent demonstrates the
limitations of the reaction. a,a’-Dibromo-o-xylene affords
the ketone 3 (18%; side product, dispiro compound 10
(5%)), which is analogous to 2 ; no C,C-alkylation product
is formed with 1,2-bis(~-bromoethyl)benzene.When 1,2-dibromo- I ,2-dihydrobenzocyclobutene is used, an electron
transfer occurs. The trimer 11 is formed as the product of
oxidative coupling.[’]
Q
%O
\ /
11
10
The reaction of the ketone 2b with organometallic compounds (phenyllithium, phenylmagnesium bromide, methyllithium) exhibits pronounced diastereoselectivity: in
the alcohol formed, 12, the carbanion has always added
syn to the benzene moiety. The configuration of the alcohol 12a (Table 1) has been confirmed by an X-ray structure determination.[81These results are in marked contrast
to the results obtained for la;[21in the latter case, only a
small amount of diastereoselectivity is observed, which,
moreover, depends on the nature of the organometallic
agent. Attack of phenyllithium on 3 also affords only the
WoH
12a: R = Ph
12b:R=CH3
Angew. Chem. Int. Ed. Engl. 24 (1985) No. 11
Li
v
13
Ph
alcohol in which the phenyl group is syn to the neighboring benzene system.
The newly accessible ketones and alcohols described
here are of further importance for the study of unusual
carbanion structures. For example, the alcohol 12a,
formed from 2b, can be transformed into the corresponding methyl ether. The reductive cleavage of the ether with
lithium leads to the benzyllithium system 13, which exhibits intramolecular “through-space” interaction between
the carbanion moiety and the separated benzene n-systern.”’
Received: June 3, 1985 [Z 1332 IE]
German version: Anyew. Chem. 97 (1985) 959
[I] H. B. Burgi, J. D. Dunitz, E. Shefter, J . A m . Chem. SOC.95 (1973) 5065.
[2] F. R. S. Clark, J . Warkentin, Can. J . Chem. 49 (1971) 2223.
131 W. Huber, W. Irmen, J. Lex, K. Mullen, Tetrahedron Lett. 23 (1982) 3889;
K. Miillen, Pure Appl. Chem.. in press.
[4] 6a (sodium salt, prepared from 2-indanone with sodium hydride): ”CNMR([‘H&THF, - 1O”C, 100 MHz): 6 = 182.2 (C-2); 152.6, 136.0, 126.7,
122.5, 117.8, 114.8 (C-arom.);94.3 (C-3), 42.7 (C-l).-S(’’C) values for 5 ,
see J. B. Lambert, S. M. Wharry, J . A m . Chem. Sac. 104 (1982) 5857.
[S] R. Gompper, H:H. Vogt, H.-U. Wagner, Z . Naturforsch. 8 3 6 (1981)
1644.
161 Excess sodium hydride effects the reduction of the non-enolizable ketone
2b to the alcohol.
[7] 11 exhibits stereodynamic behavior (rotation around the inter-ring single
bonds). The NMR signals are consequently broadened by exchange at
room temperature.
[XI P. Baierweck, D. Hoell, J. Lex, K. Mullen, unpublished.
191 P. R. Peoples, J. B. Grutzner, J . A m . Chem. Soc. 102 (1980) 4709; D.
Hoell, J. Lex, K. Mullen, unpublished.
Extensions of the Tricyclooctanone Concept.
A General Principle for the Synthesis of
Linearly and Angularly Annelated Triquinanes
By Martin Demuth* and Werner Hinsken
As an extension of our tricyclooctanone concept[’]for
the synthesis of enantiomerically pure cyclopentanoid natural products, we present here a variant,[‘’ which leads to
target structures that, using the original concept, would be
difficult to obtain. Applying the new strategy, the linear
anti-annelated triquinane skeleton 9I3j and its isomer 15
with angularly joined rings are accessible in only a few
steps.[41They are, in our opinion, suitable precursors for
hirsutene 10 and 5-oxosilphiperfol-6-ene 16, respectiveiY.[51
The light-induced oxadi-n-methane rearrangement of
bridged p,y-unsaturated ketones again serves as the key
step. Instead of constructing this type of chromophore via
a Diels-Alder reaction of 1,3-dienes with ketene equivalents,”] the addition of an acetylene equivalent (e.g., maleic
anhydride) to siloxy-substituted dienes (6 and 12) is
used.[‘] From the adducts (7 and 13, respectively) the photoreactive substrates (8 and 14) are obtained and subsequently undergo triplet-sensitized rearrangement to 9 and
15, respectively. The use of optically active dienes in this
new route is advantageous. Both 6 and 12 are derived
from a compound (1 in Scheme 1) whose enantiomers are
accessible in very good yields and high optical purities.”]
At first, racemic 1 was employed.
The cis-hydrindenone 518](Scheme 1, hirsutene project)
could be prepared in good yield in four steps starting from
the known compound 2 ( 1 -+ 2).19] The cis configuration is
[*I
Priv.-Doz. Dr. M. Demuth, W. Hinsken
Max-Planck-lnstitut fur Strahlenchemie
Stiftstrasse 34-36, D-4330 Miilheim a. d. Ruhr (FRG)
0 VCH Veriaysyesellscha~mbH. 0-6940 Weinheim. 1985
05?0-0833/85/1 lIl-09?3 $ 02.50/0
973
established in the first step, a highly selective Birch reduction (2-3).I9l The introduction of the 6,7 double bond
( - 5 ) was achieved, after protection of the alcohol 3 (+methoxyethoxymethyl ether 4),18]by oxidative transformation
of the trimethylsilyl C-5,6 enol ether of 4 (main product at
- 78 "C, 2 min). The method of kinetic formation of enol
ethers1"' proved valuable both in this and in the following
step. Thus, it was possible to synthesize the siloxydiene 6Is1
nearly quantitatively from 5 at -78°C in 5 min and to
react it, without purification, with rnaleic anhydride at
room temperature. This addition took place in an endo
manner, which is usual for Diels-Alder additions, and exclusively on the CI side of 6 - thus determining the desired
anti junction of the rings in the final product 9 . After hydrolysis of the resulting anhydride adduct, the diacid 718]
could be isolated in crystalline form and easily (in comparison, e.g., to the lead tetraacetate method) decarboxylated
electrolytically to 8 (carbon electrodes, 200 V potential)
(Table 1). In agreement with previous experience with
simpler substrates, the p,y-unsaturated ketone 8 underwent photochemical rearrangement to 9 upon irradiation
at /z=300 nm accompanied by the formation of a negligi-
1 R',
R2=0
3 R=H191
R1 = O t i , R2= H
4 RzMEM
I.-i*'". I
,
133,89
8 : 1 R : v = 1 7 1 8 . 1610, 1120, I O O O c m ~ ' . M S : m / z 2 8 0 ( M + ) , 2 5 0 146,
(l00"/0), 59. UV: iL,,,,(&)=295n m (140). 'H-NMR: 6=6.58 (ddd, J = 8 , 6.5
and 1.2 Hz, I H), 6.13 (dddd. J = 8 , 6.3, 1.6 and I Hz, I H), 4.73 (d, J = 7 Hz,
1 H), 4.68 (d, J = 7 Hz, 1 H). 4.0 (dd, J = 10 and 5.8 Hz, I H), 3.60-3.74 (m,
2H), 3.5-3.56 (m,ZH), 3.37 (s, 3H), 2.94 (ddd, 3=6.3, 3.4 and 1.2 Hz, IH),
2.71(dddd,J=6.5,4,2.6andI Hz,lH),2.46(dd,J=19.1and?.6Hz,lH),
1.94-2.07 (m,I H), 2.0 (dd, J = 19.1 and 4 Hz, I H), 1.85-1.94 (m, I H), 1.611.83 (m, 2H), 1.03 ( 5 , 3 H ) , 0.92-1.08 (m. IH). "C-NMR (100.6 MHz):
8 ~ 2 1 2 . 9s , 139.2 d, 127.3 d, 94.6 t, 79.5 d, 71.7 t, 66.8 t, 59.0 q, 54.9 d, 49.9 d,
47.3 s, 40.7 d, 36.9 t, 32.2 t, 25.3 t, 24.4 q
9 : 1R: v = 1712, 1100, 1000 c m - ' . MS: m/z 280 ( M + ) ,204, 176, 148. 133, 89,
59 (10Oa,6). U V : A,,,.,,(&)=280 nm (65). 'H-NMR: 6=4.67 (d. J = 7 Hz, I H),
4.58 (d, J = 7 Hz, 1 H), 3.80 (dd, J = 6 und 6 Hz, I H), 3.61-3.65 (m, 2H),
3.49-3.53 (m, 2 H), 3.36 (5, 3 H). 2.97 (dd, J = 5 and 10.8 Hz, I H), 2.56 (ddd,
J=6.3, 9.1 and 9.1 Hr, I H), 2.36-2.45 (m, 2H), 2.20-2.30 (m,I H), 1.97-2.06
(m,2H), 1.66-1.86(m,3H), 1.17(s,3H), 1.09-1.22(m, 1H). "C-NMR(62.9
MHz): 6=216.1 S, 94.4 t, 78.9 d, 71.8 t, 66.9 t, 63.3 s, 58.9 q, 55.1 d, 47.8 d,
44.9 t, 41.3 d, 36.7 d, 36.0 d, 34.3 d, 27.3 t, 24.4 q
14: IR: v = 1715, 1610, 1100, 1050, 1005 cm-'. MS: m / z 280 ( M + ) ,204, 175,
162, 147, 130, I 18, 105, 89 (l0Oo/o), 59. UV:A,,,(&)=297 nm (118). 'H-NMR:
6=6.24 (d, J = 8 Hz, 1 H), 6.21 (dd, J=5.2 and 8 Hz, 1 H), 4.66 (d, J = 7 Hz,
I H), 4.62 (d, J = 7 Hz. 1 H), 3.76 (dd, J=7.6 and 9.5 Hz, 1 H), 3.59-3.65 (m,
2H), 3.47-3.51 (m, 2H), 3.34 ( s , 3H), 2.98 (dddd, J=2.6, 2.6, 3.3 and 5.2 Hz,
1 H), 2.23 (d, J= 18 Hz, 1 H), 2.13-2.28 (m. IH), 1.94 (d, J = H z , 1 H), 1.78
(dd, J = 2 . 6 and 13 Hz, I H), 1.68-1.81 (m, 3H), 1.62 (dd, J = 3 . 3 and 13 Hz,
1 H), 0.97 (s, 3H). "C-NMR (75.5 MHz): 6=?13.9 S, 143.5 d, 129.5 d, 94.9 t,
85.4 d, 71.7 t, 66.8 t, 58.9 q, 50.5 d , 49.6 s, 46.9 s, 42.6 t, 39.2 t, 29.1 t, 28.4 t,
17.4 q
15: I R : v=1715, 1113, 1050, 1030 cm-I. MS: m / z 280 ( M + ) ,224, 204, 190,
174, 149, 146, 105, 89 (100%), 59. UV: d,,,,(&)=284 nm (166). 'H-NMR:
6=4.75 (d, J = 7 Hz, I H), 4.7 (d, J = 7 Hz, 1 H), 4.2 (dd, J = 8 . 7 and 8.7 Hz,
.1 H),3.6-3.73 (m, 2H),3.5-3.57 (m, 2H), 3.38(s, 3H), 2.41 (dd, J=5.5 and 5.5
Hz, I H), 2.1-2.33 (m. 4H), 1.52-1.98 (m,5 H ) , 1.39 (dd, J = 2 . 2 and 14 Hz,
a, b :75%
6 2
Table I. Spectroscopic data for compounds 8 , 9 , 14, and 15. IR in CHCl?:
U V in ethanol: 'H-NMR: 270 MHz. in CDCI,: "C-NMR: in CDCI, lal.
1H),0.81 (s,3H). "C-NMR(75.5 MHz):6=213.7 s,95.4t,83.6d,71.8t,66.9
t, 60.3 s, 58.9 q. 56.1 s , 48.3 t, 43.6 d, 38.3 d, 36.5 t, 38.4 t, 28.3 t, 28.2 d, 13.7
-
c, d : 38%
C
d
E
0
MejSiO
I
M
ble amount of a side
(reaction time 3 h, 72%
yield after purification on silica gel) (Table 1).
The reaction sequence for the synthesis of the angularly
fused isomeric triquinane 15 (Scheme 2, oxosilphiperfo-
H
6
e, f
[a] Correct elemental analyses.
5
5-7
: 50%
d_
d
0
Me3SiG
E
M
5
12
7
8
h
2 R=H
11
I
e, f
MEM (73%)
OMEM
A
0
55 %
11 -13
60%
OMEM
Aco2H
G
C02H
13
h 70%
Scheme I. Synthesis of 9. The sequence was carried out first with racemic
material [14]. a) Li/NH,, -78°C [9]. b) Methoxyethoxymethyl chloride, ethyldiisopropylamine, CH,CIZ, room temperature. c) Lithium diisopropylamide,
trimethylsilylchloride, - 7 8 T , analogous to [lo]. d) 2,3-Dichloro-5,6-dicyano-p-benzoquinone, benzene, room temperature, 24 h. e) Maleic anhydride,
no solvent, room temperature, 4 h. f) H 2 0 . g) 90% aqueous pyridine, triethylamine, 4-terr-butylcatechol, electrolysis, analogous to [12]. h) Acetone ( I %
solution), irradiation at A= 300 n m (Rayonet apparatus with RPR-3000
lamps), room temperature, 3-4 h.
0 YCH Verlagsgesellschaft mbH. 0-6940 Weinheim. 1985
14
9
c-
i
I
9
MEM = - C H ? O C H Z C H ~ O C H ~
974
z
72 %
H
10
R
15
16
Scheme 2. Synthesis of 15. The sequence was carried out first with racemic
material [4]. b, c. and e-h have the same meaning as in Scheme 1.
0570-0833/85/1111-0974
$02.50/0
Angew. Chem. lnf. Ed. Engl. 24 11985) No. I 1
lene project) began with the facile synthesis of the diene
12.[*l 12 could be prepared by kinetic deprotonation of
11 ,I8]which gave, as expected,[I3l exclusively the 5,6-enolate, and subsequent trapping of the enolate with trimethylsilyl chloride according to the method of Corey.L’ol12
was directly used for the subsequent step. The introduction
of the etheno bridge [12+13 (exclusively endo adduct)+14 (Table l)][” was achieved analogously to the
synthesis of 8 (from 6) in comparable yields. The photorearrangement 14 + 15 (Table 1 j (4 h irradiation time, 70%
yield after purification on silica geljl”l confirmed, along
with the spectroscopic results, the structure of the enone
chromophore of 14. The possible isomeric arrangement in
which the oxoethano and etheno bridges are interchanged
would have resulted in a stereoisomer of 15 with an unrealistically strained trans ring junction for ring A. The
successful oxadi-n-methane rearrangement of 14 to 15
was not predictable a priori. For instance, a few examples
of bridgehead-substituted 0,y-enones have been found that
are unreactive upon irradiation.“, I4l
The efficiency and ease of the photorearrangements presented here further support the preparatively interesting
applications of specific light-induced processes. The remaining functionalization of 9 to 15 and of 10 to 16
should be realizable using relatively simple procedure^.^'^^
Received: June 25, 1985:
revised: August 23, 1985 [Z 136411365 IEI
German version: Angew. Chem. 97 (1985) 974
[ I ] M. Ikmuth, K. Schaffner, Angew. Chem. 94 (1982) 809; Angew. Chem.
l n r . Ed. Engl. 21 (1982) 820; M. Demuth, Chimia 38 (1984) 257.
[2] W. Hinsken, Dissertotion, Max-Planck-lnstitut fur Strahlenchemie, Mulheim a. d. Ruhr und Universitat Bochum; M. Demuth, B. Wietfeld, W.
Hinsken, K. Schaffner, Proc. Xrh IUPAC Symp. Phorochem.. Presses Polytechniques Romandes, Lausanne 1984, p. 81.
[3] The construction of the same carbacyclic skeleton using the original
concept is appreciably more difficult. M. Demuth, A. Cinovas, E.
Weigt, C . Kriiger, Y.-H. Tsay, Angew. Chem. 95 (1983) 747; Angew.
Chem. Inr. Ed. Engl. 22 (1983) 721; Angew. Chem. Suppl. 1983. 1053.
[4] The absolute configurations shown serve to elucidate the concept and
apply to the target structures. Configurational assignment of 10 and 16,
respectively: D. H. Hua, G. Sinai-Zingde, S . Venkataraman, J . Am.
Chem. Soc. 107 (1985) 4088 and L. A. Paquette, R. A. Roberts, G. J.
Drtina. ibid. 106 (1984) 6690.
[ 5 ] Review on current syntheses of polyquinane compounds: L. A. Paquette, Top. Curr. Chem. 119 (1984) l .
[6] In the dienes 6 and 12, the trimethylsilyl and MEM residues may be
replaced by acetyl and tert-butyl groups, respectively. The combination
used here has proved especially suitable in the present case.
[7] Z. G. Hajos, D. R. Parrish, J . Org. Chem. 39 (1974) 1612, 1615; U. Eder,
G. Sauer, R. Wiechert, Angew. Chem. 83 (1971) 492; Angew. Chem. In!.
Ed. Engl. 10 (1971) 496.
181 The analytical data for all new products are in agreement with the assigned structures.
191 C. B. C. Boyce, J. S. Whitehurst, J. Chem. SOC.1960, 4547.
[lo] E. J. Corey, A. W. Gross, Tetrahedron Lett. 25 (1984) 494.
[ I 11 The G C analysis of the crude mixtures after irradiation shows 88-90% of
the oxadi-n-methane products 9 and 15 as well as 5% of a product
formed by 1,3-acyl shift (Norrish type I) from 8 and 14, respectively.
[12] C. B. Warren, J. J. Bloomfield, J. S . Chickos, R. A. Rouse, J . Org. Chem.
38 (1973) 401 I.
[13] W. Weber, D. Spitzner, W. Kraus, J . Chem. SOC.Chem. Commun. 1980,
1212.
[ 141 B. Wietfeld, Disserfalion, Max-Planck-Institut fur Strahlenchemie, Mulheim a. d. Ruhr und Universitat Bochum 1984.
[IS] According to preliminary experiments the crucial step, the lateral opening of the cyclopropane ring of 9 and 15, can be achieved selectively
under Birch-type conditions; moreover, 15 can be methylated regioselectively in the a-position t o the keto group.
Angew Chem I n r . Ed. Engl. 24 (1985) N o 1 1
Preparation and Structure of a
Diphosphorus Compound with Positive Charges on
the Two Directly Bonded Phosphorus Atoms**
By Dietmar Schomburg, Gerhard Bettermann.
Ludger Ernst. and Reinhard Schmutzler*
The P-P single-bond distance in diphosphorus compounds varies only slightly, depending on the oxidation
state and/or coordination number of the phosphorus
atoms involved, and is usually around 220 ~ m . l ’ - ~
It I was
therefore of particular interest to determine whether this
constant P-P bond length is also observed when both
phosphorus atoms bear a formal positive charge. Two opposing effects should be operative in this case: on the one
hand, the electrostatic repulsion of the positive charges
should lead to a lengthening of the P-P distance; on the
other hand, the orbital contraction resulting from the proximity of two positive charges could lead to a shortening of
the P-P distance.
To the best of our knowledge, the double quaternization
of two directly bonded phosphorus atoms, for example, by
alkylation of a 1 3 P 1 4 P + species, has not yet been
achieved.“’ Presumably, the nucleophilicity of the 1’ phosphorus atom is strongly decreased by the proximity of the
positive charge.”.’’ I n studies carried out by Noth et a1.l6l
and Seidel,[’’ attempts to alkylate several diphosphanes
with alkyl iodides resulted in cleavage of the P-P bond and
disproportionation rather than quaternization of directly
bonded phosphorus atoms. In the case of 2, however, th;
bridging of the two phosphorus atoms by the N.N’-dimethylurea groups should render cleavage‘of the P-P bond
more difficult.
We have developed a simple synthesis of compound 1
(and of its dimer resulting from chloride bridging).“] The
positive charge in 1 can, as part of the assumed zwitterionic system, presumably be delocalized optimally over
three directly neighboring nitrogen atoms. Consequently,
FI
;
B
1
2
P
0
3
[*] Prof. Dr. R. Schmutzler, DiplLChem. G. Bettermann
lnstitut fur Anorgdnische und Analytische Chemie der
Technischen Universitat
Hagenring 30, D-3300 Braunschweig (FRG)
Priv.-Doz. Dr. D. Schomburg [+I, Priv.-Doz. Dr. L. Ernst
Gesellschaft fur Biotechnologische Forschung mbH
Mascheroder Weg I, 0-3300 Braunschweig-Stockheim (FRG)
[‘I X-ray structure analysis.
[**I This work was supported by Bayer AG, Hoechst AG, and the Fonds der
Chemischen Industrie.
0 VCH Verlagsgesellschaft mbH, 0-6940 Wernheim, 1985
0S70-0833/85/1111-0975 $ 02.50/0
975
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