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Tricarbonyl(1-methyl-3 5-diphenyl-4-thiabenzene)chromium(O).

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Table 1 Spectroscopic data of new compounds (5)-(9)
[al.
'1
UV Lax
Inml [bl
Compound
'H-NMR (CDCh, TMS. &-values)
IR [cm-
(5)
1 15 (d,J = 4 Hz, 1 H), 20(s,4H). 2.50 ( d , J = 4
Hz. 1H). 2.62 (d, J = 6 Hz. 2H), 5.3-60 (m,
3 H), 6.35 (d, J = 1 I Hz. 1 H)
(6)
0 . 3 0 ( d , J = 3 Hz, l H ) , 2 . 2 6 ( d , J = 3 H z , l H ) ,
2.4-2.8 (m, 4H), 5.1-5.9
(m, 5H), 6.0 (d,
J = 12 Hz, 1 H)
1.93 (s, 6H), 2.0-30 (m, 5H). 3.36 (d, 5=13
3010, 2915, 1710, 1595,
1420, 1285. 1250, 1080,
1048. 1012, 920, 848,
775, 702
3050, 2940, 2860, 1600.
1425, 948, 937,900, 848,
738. 705, 682
2950, 1730, 1365, 1255,
1225, 1190, 1020, 1005,
957, 940, 880, 791, 742
3015, 1735, 1450, 1370.
1238. 1050, 1017, 736,
708
3500, 3030, 1380, 1282.
1088, 1061. 930. 742,
709
17)
Hz,lH),5.3-5.9(m,5H),6.tO(dd,J=4Hz,
10HZ. 1 H)
2.00(~,3H),2.34(dd,J=8H~,14H~,lH),
3.50 (br. s., 2H), 3.99 (dd. J = 8 Hz, 14 Hz.
1 H), 5.1-5.9
(m, 6H), 6.01 (d, J = l O Hz,
1 .80 (dd, J = 7 Hz, 13 Hz, 1 H + -OH), 2.95
(dt.J= 12 Hz, 2 Hz, IH), 3.52(dd,J=l Hz, 12
Hz, 1 H), 3.91 (dd, J = 7 Hz. 13 Hz, lH),
5 2-5.8 (m, 6H). 5.95 (d, J = 12 Hz, I H)
(8)
(9)
245
275
247
244, 276, 355
246,282. 356
[a] All the new compounds gave satisfactory elemental analyses and/or mass spectrometrically determined molecular weights.
[h] In ethanol
[ I ] a) E. Vogel, Chem. SOC.Spec. Publ. (London) 21, pp. 113 (1967); b) Proc. Robert A. Welch Found. Conf. Chem. Res. 12, 214 (1969); c) Pure Appl. Chem.
28, 355 (1971); d) Rheinisch-Westfal. Akad. Wiss., Nat. 1ng:Wirtschaftswiss., Vortr. 288 (1973).
121 S. Masamune, D. W. Brooks, Tetrahedron Lett. 1977, 3239.
[3] Substituted homoazulenes have previously been prepared by two routes: a) S.
Masamune. D. W. Brooks, K. Morio, R. L. Sobczak, J. Am. Chem. Soc. 98,
8277 (1976): b) L. T. Scott, W. R. Brunsoold, ibid. 100, 4320 (1978).
[4] a) L. T. Scott. J. Chem. SOCChem. Commun. 1973,882: b) L. T. Scott, M. A.
Minfon. M. A . Kirms, J . Am. Chem. SOC.102, 6311 (1980).
[S] E. 1. Carey. M. Chaykovsky, J. Am. Chem. SOC.87,1353 (1965).
[6] R. H. Shapiro, Org. React. 23, 405 (1976).
[7] See, for example. a) S. Moon. J. Org. Chem 29. 3456 (1964); b) R. J. Ouelleffe, D. Miller. A . South, Jr., R. D. Robins, J. Am. Chem. SOC.91, 971
(1969)
[XI J. Tsuy, 7 Yumaknwa, M. Kaifo, T. Maudni, Tetrahedron Lett. 1978, 2075.
191 L. T Scott e f ol., unpublished results.
-
Complex (2) is formed by reaction of the thiinium salt
(I)[') with potassium tert-butanolate and triacetonitrile(tricarbonyl)chromium(O) in dimethylsulfoxide (DMSO) as a
dark red crystalline, air stable solid; yield 75%'*1.
In addition to the molecular ion, the mass spectrum of (2)
contains readily characterizable fragments formed by ligand
cleavage. IR- and NMR-spectroscopic data of (2) are consistent with coordination of the heterocycle to the metal (Table
1). The highest wave number CO band of (2) is shifted to
lower wave numbers by 18 cm-l, relative to the analogous
thiabenzene oxide complex (4)['1.
Tricarbonyl(l-methyl-3,5-diphenyl-h4thiabenzene)chromium(0)"I
(4)
By Lothar Weberr']
h4-Thiabenzenes merit interest in being examples of sixmembered ring systems with 6~-electrons.Some derivatives,
e.g. (3), have been previously generated and studied in solution by means of 'H-NMR spectroscopy, but their inherent
thermolability precluded their isolation and complete characterization"'. We have, for the first time, been successful in
stabilizing a thiabenzene derivative as a ligand in a transition
metal complex: the title compound (2).
H5C6
m
$
C6H5
BF$
(21, MS: m/e=4M) (M+),
372 (M-CO)+, 344 (M-ZCO)+, 316 (M-3CO)+,
300(M-3CO, -CHI, - H ) + , 269(CsH&Hs)2Cr)+. 217 (CsH,(C6H5),)+; IR
(CH2Cl2): 1952 vs, 1888 S, 1851 s cm-' (4CO); 'H-NMR ([D61acetone, TMS):
6 ~ 2 . 2 1(s, CH?), 3.39 (d, 2-, 6-H,J = 1.5 Hz), 6.74 (t.4-H, J = 1.5 Hz), 7.33-7.89
(m, C&); "C-NMR ([D6)acetone, 6(C0)=206.0): 6=27 88 (C-2, -6), 41.48
(CH,), 90.54 (C-4). 106.28 (C-3, -5), 128.89, 129.32, 129.59 and 141.64 (C6Hs).
237.60 (CO).
Analogue: 1R (CH2CI2): 1951 vs, 1886 s, 1850 s c m - ' (I(C0)); 'H-NMR
([D61acetone,TMS): S= 1.06 (t. CH,, J = 8 Hz), 2.49 (4. CHI, J = 8 Hz), 3.39 (d,
2-, 6-H. J = 1 Hz), 6.72 (1, 4-H, J = 1 Hz), 7.36-7.78 (m, C,H,)
KOtBu
+ ( C H S C N ) ~ C ~ ( C O---+
)~
DMSO
c' H3
(1)
['I
Table 1. Selected data of complex (2) and its analogous 1-ethyl-complex.
Dr. L. Weber
Fachbereich Chemie der Universitat Essen-GHS
Universitatsstr. 5-7. D-4300 Essen 1 (Germany)
p*1 Transition Metal Sulfur Ylide Complexes, Part 10. This work was supported
by the Deutsche Forschungsgemeinschaft The X-ray structure analysis of
(2) was carried out by Dr. R. Boese. I am grateful to Prof. Dr. C Schmidfor
helpful discussions. Part 9 L. Weber, Chem. Ber. 114, 1 (1981).
Angew. Chem. Int. Ed. Engl. 20 (1981) No. 3
The enhanced donor capacity of the ligand (3) in complex
(2) relative to the thiabenzene oxide ligand in complex (4) is
revealed by a downfield shift of the 13C0 resonance of 2.12
PPm.
The X-ray structure analysis of (2) clearly establishes that
the chromium atom is q5-bonded to the five carbon atoms of
the heterocycle, which lie in a planar arrangement. The sulfur atom is located 0.76 A above this plane and does not interact with the metal: d(Cr-S) = 2.88 A[41.Thus the properties of thiabenzene (3) as a ligand can best be described in
terms of an ylide and not as an arene.
The reaction of (1) with tricarbonyl(cyc1oheptatnene)molybdenum(0) or with tricarbonyl(cyc1oheptatriene)tungsten(0) affords a molybdenum (42% yield, m. p. = 169 "C,decamp.) or tungsten analogue (47% yield, m. p. = 132 " C , de-
0 Verlag Chemie, GmbH, 6940 Weinheim, 1981
0570-0833/81/0303-0279
S 02.50/0
279
27 5 / 278 Advertisement
comp.) respectively. The spectroscopic properties of these
purple air stable, diamagnetic solids correspond to those of
(2), indicating analogous structures.
Preliminary studies have shown, that the novel complexes
of type (2) undergo alkylation at the methyl group. Thus, the
lithiation of (2) in tetrahydrofuran at - 70 "C with the equivalent amount of tert-butyllithium and subsequent addition
of excess methyl iodide produces reddish-brown tricarbonyl(l-ethyl-3,5-diphenyl-X4-thiabenzene)chromium(O)
in 63%
yield (m.p.= 156-158 "C, decomp., see Table 1).
methodI3"]. For synthesis of the natural pr0duct1~~1,
however,
it appeared to us that ring closure at the unhindered primary
amino group, [email protected], would be more favorable.
Procedure
30 cm' of anhydrous DMSO is added to a mixture of
(CH3CN)3Cr(C0)3(1.011 g, 3.9 mmol), (1) (1.057 g, 3.0
mmol)"], and potassium tert-butanolate (0.337 g, 3.0 mmol)
under nitrogen at room temperature. The resulting dark red
solution is stirred for 1.5 h at room temperature. After evaporation of the solvent and volatile components in vucuo, the
residual red oil is taken up in CHzClz(20 cm'). The solution
is filtered through a GCfrit, and 5 cm' of methylcyclohexane
added to the filtrate, which is then slowly evaporated in uacuo until a dark red oil separates. The supernatant liquid is
decanted, and the oil washed with light petroleum (4x 10
cm'). The residue is recrystallized twice from CH,Cl,/light
petroleum and after drying in vucuo yields dark red (2); yield
0.897 g (75%), m. p. = 152-154 "C.
Received: June 6, 1980. supplemented December 19. 1980 [Z 723 IE]
German version: Angew. Chem. 93, 304 (1981)
CAS Registry numbers:
( I ) , 28275-94-7; (2). 76900-60-2 tricarbonyl(l-ethyl-3,5-diphenyl-A~-thiahenzene)chromium, 76900-61-3: tricarhonyl(l-methyl-3,5-diphenyl-A4-thiahenzene)molyhdenum, 76900-62-4; tricarbonyl(l-methyl-3.5-diphenyl-h4-thiahenzene)tungsten, 76900-63-5; tricarbonyl(cycloheptatriene)molybdenum, 1212577-8; tricarbonyl(cyc1oheptatriene)tungsten. 12128-81-3; (CH,CN).O(CO),.
16800-46-7
[ l ] A . G.Hortmunn, R . L. Harris. J. A. Miles, J. Am. Chem. SOC.96,6119(1974):
B. E. Muryanofl. J. Stuckhouse. G. H. Senkler, Jr.. K. Mislow. rbid. 97, 2118
(1975).
(21 Here only one isomerically pure compound is obtained In the reaction of 1methyl-3,5-diphenylthiabenzene1-oxide with (CH2CN)3Cr(CO)2two isomers are generated which differ in the orientation of the S(O)CH,-group to the
chromium atom 131.
131 L. Weber, C. Kniger, Y.-H. Isay. Chem. Ber. 111, 1709 (1978).
[4] Space group P2,/n, monoclinic. cell constants: u = 10.004(3), b = 13.073(6),
c = 14.840(8) A: p=101.75(3)". 2 = 4 , V=1900 A
'.
A Novel Method for Preparation of Ansapeptides;
Synthesis of Model Peptide Alkaloids
By Ulrich Schmidt, Helmut Griesser,
Albrecht Lieberknecht, and Jorg Tulbiersky[']
In the course of experiments directed towards the synthesis
of peptide alkaloids"] we have developed a novel ring closure method for formation of these 13- and 14-membered
ansa peptides. We investigated the cyclization using the
model compound ( I ) , which differs principally from the natural product by substitution of a p-phenoxyamino acid by pphenoxypropionic acid. Rapoport et al. 11' had previously prepared (1) by ring closure at @using the nitrophenyl ester
1'1 Prof. Dr. U Schmidt, Ing. H. Griesser, Dr A Lieherknecht, Dr. J. Talbier-
["I
sky
Instilut fur Organische Chemie, Biochemie und Isotopenforschung der Universitat
Pfaffenwaldring 55. D-7000 Stuttgart 80 (Germany)
Synthesis of Peptide Alkaloids. Part 1. Part 30 of Amino Acids and Peptides. This work was supported by the Fonds der Chemischen Industrie and
by BASF AG-Part 2 9 U . Schmidf, E. Ohler. J. Hausler, H. Poisel, Chem.
Org. Naturst. 37, 251 (1979); Part 2 8 E. Ohler, U. Schmidt, Chem. Ber. 112,
107 (1979).
280
0 Verlag Chemie. GmbH. 6940 Weinheim. 1981
For the ring closure, a dioxane solution of the pentafluorophenyl ester (2)14] was added dropwise to a rapidly stirred
suspension of Pd/charcoal in dioxane at 95°C into which
hydrogen was passed. The solution contained 1 mol4-pyrrolidin~pyridine'~]
per mol (2) as catalyst and 2% alcohol (with
respect to the solvent). The benzyloxycarbonyl group is first
removed by hydrogenolysis, and ring closure apparently occurs on the wamino ester which is still adsorbed on the catalystl91.
Using conditions of dilution, 50% of (1) was formed (determined gas chromatographically). The yields drop dramatically if alcohol is not added or its concentration exceeds 5%,
if the reaction temperature is lower than 70 "C and if other,
or no bases are used as catalysts (e. g. pyridine, N-methylimidazole). Under these conditions dimeric cyclopeptide is only
obtained in small amounts, whereas it becomes the major
product (yield 45%) if the reaction is carried out in ethyl acetate at 75 "C.
The smallest bridge in para-ansa compounds, which can
be formed by ring closure of a para-substituted aromatic
compound in satisfactory yields, contains ten members. In
the model compound ( I ) , which has a ten-membered bridge,
the formation of the bridge is made all the more difficult by
the s-trans-conformation of both amide groups.
We obtained the 13-membered ring compound (3), which
has a 10-membered metu-bridge, in 80% yieldI6];(3) is therefore considerably more easily formed than ( I ) . Up till now,
the shortest meta-bridge to a benzene ring, formed by ring
closure in satisfactory yield, is nine-membered (resorcinol
heptamethylene ether)"'.
The method described here leads to formation of difficultly accessible compounds of this type in up to three or four
times better yield than the nitrophenyl ester routeIz1.A further advantage is the considerably easier work-up, since the
reaction solution does not contain any trifluoroacetic acid
(for deblocking the Boc-group) or high boiling solvent (dimethylacetamide).
Procedure
A solution of (2)[41(165 mg) in 20 cm' dioxane is uniformly
injected over 18 hI91 to a rapidly stirred suspension of Pd/activated charcoal (600 mg, 5%) in 350 cm' pure dioxane at
90 "C (temp. in flask), which contains 7 cm3 ethanol and 40
mg 4-pyrrolidinopyridine. At the same time, hydrogen is
passed through the solution. The solution is filtered, concentrated, and the product isolated using medium pressure chromatography on silica gel (dichloromethane/methanol 98: 2);
(yield 39 mg, 50%) of (1). The chromatographically pure
-27.3 (c=1.15, ethanol)) is dissolved in 20
product
cm3 water-free ether and after a few hours ca. 2mg racematers1precipitates (M. p. = 202-205 "C). Concentrating the
mother liquor yields the S-enantiomer as an oil
(
= - 28.1 (c=0.56, ethanol)). The racemate and S-en-
0570-0833/81/0303-0280
S 02.50/0
Angen'. Chem. Int. Ed. Engl 20 (1981) No. 3
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