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X-Ray Structure Determination of [-(Phenylsulfonyl)benzyllithium-Tetramethylethylenediamine]2 Chirality of an -Sulfonyl УCarbanionФ.

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Table 2. Relative vields 1%1 of 9-methvl-9-BBN and 9-ethyl-9-BBN as a function of the >BH/CO ratio
compound [bl
Yield [a]
30. I
[a] G C peaks; conditions for separation: capillary column (36 m); dexsil300; injection block: 150°C; column: 40-280°C (6"/rnin). [h] Standard conditions: carhonylmetaf compound and 9-H-9-BBN in mesitylene ( M ) or in nonane (N) heated for t 1 h at Z 140°C. [c] Portionwise addition ( t 3 h) of solid 9-H-9-BBN to the
solution of Fe(CO), at 140°C. [d] Heated at t 9 O T .
complexes are formed as intermediates in the synthesis (cf.
Scheme I )
+ 9-H-9-BBN
9-CH3- 9-BBN
Scheme I. Possible mode or the 9-alkyl-9-BBN formation
Different rates of the reduction and CO-insertion reactions lead, depending upon the amount of monomeric 9-H9-BBN available in solution, to varying amounts of 9-methyl-, 9-ethyl-, and higher 9-alkyl-9-BBN homologues.
Thus, at low >BH/CO ratios the amount of 9-methyl-9BBN drastically decreases, e.g. on slow addition of 9H-9BBN (cf. Tables 1 and 2).
We presume that the higher 9-alkyl-9-BBN compounds
(alkyl Z C,H,) are only formed on polynuclear metal clusters or on the surfaces of metal particles which separate
from the original homogeneous solutions of the metal carbonyls.
The composition of the 9-alkyl-9-BBN mixture depends
on the molar ratio of the reactants and on the reaction conditions, i.e. the temperature, the heating rate, or additives,
e.g. alkali metal alkoxides. The metal carbonyl/9-H-9BBN system is thus suitable as a readily variable, easily
accessible reaction mixture for the investigation of the
Fischer-Tropsch synthesis.
Received: March 27, 1985 [Z 1176 IE]
German version: Angew. Chem. 97 (1985) 6oo
CAS Registry numbers:
9R-9-BBN (R=methyl), 23418-81-7; 9R-9-BBN (R=ethyl), 52102-17-7; 9R9-BBN (R=propyl), 1127-78-2; 9R-9-BBN (R=butyl), 23532-74-3; (9BBN)?O, 74744-62-0; 9H-9-BBN, 280-64-8; Fe(Co)5, 13463-40-6; Fe2(Co)g,
15321-51-4: C O ~ ( C O )10210-68-1:
Fe3(Co),2, 17685-52-8.
[I] Patent ( D R P 484337), entitled "Verfahren zur Gewinnung mehrgliedriger
Paraffi nkohlenwasserstoffe aus Kohlenoxyden und Wasserstoff auf katalytischem Wege", filed 60 years ago (July 22, 1925) by Franz Fischer and
Hans Tropsch (Miilheim a. d. Ruhr).
[2] Ullmanns Encyklopadie der Technischen Chemie, Vol. 14, 4th Edit., Verlag
Chemie, Weinheim 1977, p. 329-355; R. B. Andersen: The FischerTropsch Synthesis. Academic Press, London 1984.
[3] a) C . Masters, Adu. Organomet. Chem. 17 (1979) 61; C. K. Rofer-De
Poorter, Chem. Rea. 81 (1981) 447; G. Henrici-Olive, S. Olive: The Chem-
Angew. Chem. Inl. Ed. Engl. 24 (1985) No. 7
istry ofthe Catalyzed Hydrogenation of Carbon Monoxide. Springer, Berlin 1984; b) S. L. Suih, K. C. McMahon, L. M. Tau, C . 0. Bennett, J . Cafal. 89 (1984) 20; c) w . A. Herrmann, Angew. Chem. 94 (1982) 118; Angew. Chem. Int. Ed. Engl. 21 (1982) 117.
Compare the yields of the Fischer-Tropsch products with those of other
metal carbonyl reductions: A. Wong, J . D. Atwood, J . Organomel. Chem.
199 (1980) C 9 ; 210 (1981) 395; C. Masters, C. van der Woude, J. A. van
Doom, J . A m . Chem. Sac. 101 (1979) 1633.
a) R. Koster, Angew. Chem. 72 (1960) 626; h) R. Koster, P. Binger, Inorg.
Synth. 15 (1974) 141; c) cf. Houhen-Weyl: Methoden der Organischen
Chemie, Ed. X111/3a, 4th Edit., Thieme, Stuttgart 1982, p. 330; d) see
[ k ] , p. 339 f.
a) For determination of the hydride number ( H Z B B Y )the
, 9-H-9-BBN
consumed by the metal carbonyls was measured at G 140°C [6b]:
Fe(C0)5 ( H Z s s N = 11); Fe2(C0)9 (20); Fe,(CO),> (26.5); C O ~ ( C O (16).
The consumption of open-chain alkyldiboranes(6) [5b,c] is greater ( H Z
[6h] > HZBRN);
complex mixtures of trialkylboranes, trialkylboroxines
and tetraalkyldiboroxanes; are formed; h) R. Koster, L. Synoradzki,
Chem. Ber. 117 (1984) 2850.
Experrmenlal: The yellow-orange slurry of 9-H-9-BBN [5b, c] (8.21 g, 67.8
mmol) and Fe(COjs (3.21 g, 6.16 mmol) (>BH : F e = 11.1;
>BH :CO=2.2: I ) in nonane ( = 8 mL) was heated slowly under protective gas; the color changed from orange-yellow through yellowish gray
(50-SOT) to black. At 2 8 0 ° C 4.5 mmol of gas (MS: 68.5% H2, 31.9Oh
CHI, = 1.3% C2Hh, = 1% C4HIO)were liberated. After stirring for =30
min (bath: = 140°C; exothermic reaction up to = 160°C) nonane (5.8 g ;
14 torr; bath: 5 7 0 ° C ) and a 9-alkyl-9-BBN mixture [ t1 g (calc. 0.96 9);
0.001 torr; bath: C90"Cl (S"B= 88.2) were distilled off (composition: cf.
Table 1) under vacuum. From the highly viscous residue by sublimation
in vacuo (0.001 torr; bath: 90- IOOT) 7.75 g(calc. 7.95 g) of colorless (9BBN)20 remained [MS: m/z=258; S"B= 59.31. After heating in boiling
heptane one obtains 520 mg Fe-containing black solid ( ~ 6 7 %
See [Sc]. pp. 816, 819.
9-D-9-BBN [Sc] transforms at 2 140°C via dehydroboration/deuterioboration into partially deuterated 9-H-9-BBN compounds.
X-RaY Structure Determination of
Chirality of an a-Sulfonyl "Carbanion"""
By Gernot Boche,* Michael Marsch, Klaus Harms, and
George M . Sheldrick
Dedicated to Professor Rolf Huisgen on the occasion of
his 65th birthday
a-Sulfonyl "carbanions" ( R1R2C"-S02R3M @)play an
important role in synthetic chemistry."' The high acidity of
[*] Prof. Dr. G. Boche, M. Marsch
Fachbereich Chemie der Universitat
Hans-Meerwein-Strasse, D-3550 Marhurg (FRG)
Prof. G. M. Sheldrick, Dr. K. Harms
Institut fur Anorganische Chernie der Universitat
Tammannstrasse 4, D-3400 Gottingen (FRG)
[**I This work was supported by the Fonds der Chemischen lndustrie
0 VCH Verlagsgesellschaft mbH, 0-6940 Weinheim, 1985
0570-0833/85/0707-0573 $ 02.50/0
the corresponding C H compounds and the fact that optically active a-sulfonyl “carbanions” can be prepared from
optically active sulfones led early to numerous experimental[21and theoreticall3’ studies into the nature of the stabilization of a negative charge by a neighboring sulfonyl
group (-s02R3) and the origin of the chirality in the “carbanion.” The central question was whether the anionic C
atom was pyramidal or planar, and, if planar, what conformation the substituents on the S atom adopted with respect
to those on the anionic C atom. The position of the counterion Me is of particular current interest.
Fig. 1. Crystal structure 01 I Space group PnaZ,, a = 1705.1(6),b = 1001.7(2),
c=2375.9(30) pm, Z=8 (one dimer per asymmetric unit). R =0.064 for 3103
reflections with F>3u(F). The dimer has approximately C , symmetry, but
could not be brought into accord with a n inversion center of a centrosymmetric space group. The probable direction of the polar axis was determined by
the use of a n q-refinement [6]. The hydrogen atoms were refined according to
a riding model with C-H 96 pm. An attempt to refine freely the H atoms on
C(I) and C(1’) gave only approximate positions with large standard deviations. Important distances (mean values) [pm] and bond angles (mean values)
[“I:C(I)-S 164.1(5); C(8)-S 178.4(5); S - 0 146.5(4); Li-N 213.6(10); Li-0
189.0(9); C(l)-C(2) 143.7(8). 0-S-0 115.4(2); S-C(1)-C(2) 125.8(4). Dihef45.6(6) and ? 175.4(5):
dral angles (mean value) [“I: O-S-C(I)-C(Z)
+70.4(6); S-C(I)-C(Z)-C
f3.1(9) and ? 176.8(30).
Further details of the crystal structure investigation may be obtained on request from the Fachinformationszentrum Energie Physik Mathematik, D7514 Eggenstein-Leopoldshafen 2, by quoting the depository number CSD
51 257, the names of the authors, and the journal citation.
We report here the X-ray structure investigation of a (phenylsulfony1)benzyllithium-tetramethylethylenediamine
1 (Fig. 1).[4,51
1 crystallizes as a dimer in which the Li atoms are coordinated only by the tetramethylethylenediamine (TMEDA)
molecules and the 0 atoms of the sulfonyl group, but not
by the “anionic” C atoms! IR and Raman studies on
C6HSSO2CH2Liin solution indicate a contact to the C
atoms as well.[’”] In the polymeric benzyllithium-triethylenediamine complex, the Li atom bridges three carbon
atoms (corresponding to C(1), C(2), and C(3) in Fig. I)[’]
and in the monomeric 2-lithio-2-phenyl-l,3-dithiane-tetrahydrofuran-tetramethylethylenediamine,a C-Li bond to
the benzylic C atom is present.[’] Ab initio calculations on
LiCHZSOZCH3give two different Li positions as minima
on the potential
The C(1)-S distance (164.1 pm) is appreciably shorter
than the corresponding distance in sulfones (mean value of
58 bond lengths: 180.6 pm).I9] By comparison, the CS double bond in thioformaldehyde is 161.08 pm,[’O1which is
only 3 pm shorter than C(1)-S in l ! The increased C S
bond order in 1 is in accord with an increased force con574
stant in C6H5S02CH2Li,[2”1
as determined by vibrational
The S - 0 distance in 1 (146.5 pm) is only a little larger
than that in sulfones (mean value of 53 bond lengths: 143.4
~ r n ) .A
~ ~larger
S-0 distance was indicated by the force
constants of a-sulfonyl “carbanions” as determined by IR
spectroscopy.[’”] The S-C( 1)-C(2)-C
dihedral angles
show that the short C S bonds lie in the plane of the phenyl
ring, in accord with sp’ hybridization of the carbon atom
C ( l ) as well as with the results of most of the studies
(mainly kinetic)12”-”] on a-sulfonyl “carbanions” in solution. The chirality of an a-sulfonyl “carbanion” could
therefore be due to a chiral conformation and hindered rotation around the C(1)-S bond, rather than to a tetrahedral configuration of the anionic C atom.[”] U p to now, kinetically controlled anion formation has been presumed to
be responsible for the formation of a chiral conformatiOn.12a,e,k.IlThe dihedral angles around the C(1)-S bonds
(see above and Fig. 2) indicate that a local chiral conformation is thermodynamically favored in the crystal of 1 ;
the p orbital on C( 1) is approximately gauche to the two 0
atoms o n the sulfur.
0 VCH Verlagsge.selIschaJi mbH. D-6940 Weinheim. 1985
Fig. 2. Dihedral angles around the C(I)-S bonds
Received: February 14, 1985;
revised: April 24, 1985 [Z 1172 IE]
German version: Angew. Chem. 97 (1985) 577
CAS Registry numbers:
1, 96705-29-2.
[I] Reviews: J. C. Stowell: Carbanions in Organic Synthesis, Wiley, New
York 1979; P. D. Magnus, Tetrahedron 33 (1977) 2019; E. Block: Reactions of OrganosuSfur Compounds. Academic Press, New York 1978.
[2] a) D. J. Cram: Fundamentals of Carbanion Chemistry, Academic Press,
New York 1965, p. 48-52; b) F. G. Bordwell, P. J. Boutan, J . Am.
Chem. SOC.79 (1957) 717; c) W. von E. Doering, L. K . Levy. ibid. 77
(1955) 509; d) H. E. Zimmerman, B. S. Thyagarajan, ibid. 82 (1960)
2505; e) E. J. Corey, T. H. Lowry, Tetrahedron Lett. 1965, 793, 803; E. J.
Corey, H. Konig, T. H. Lowry, ibid. 1962, 515; f) R. Breslow, E. Mohacsi, J . Am. Chem. SOC.83 (1961) 4100; 84 (1962) 684; g) H. L. Goering, D.
L. Townes, B. Dittmer, J . Org. Chem. 27 (1962) 736; h) T. Durst, R.
Viau, R. Van Den Elzen, C. H. Nguyen, Chem. Commun. 1971, 1334; i)
J . W. Henderson, Q. Rev. Chem. SOC.2 (1973) 397; j) G. Barbarella, A.
Garbesi, A. Fava, J . Am. Chem. Soc. 97 (1975) 5883; k) F. G. Bordwell,
N. R. Vanier, W. S. Matthews, J. 8. Hendrichson, P. L. Skipper, J . Am.
Chem. Soc. 97 (1975) 7160; I)F. G. Bordwell, J. C. Branca, C . R. Johnson, N. R. Vanier, J . Org. Chem. 45 (1980) 3884: m) R. Lett, G. Chassaing, A. Marquet, J. Organornet. Chem. I 1 1 (1976) C 17; n) G. Chassaing,
A. Marquet, Tetrahedron 34 (1978) 1399: 0)G. Chassaing, A. Marquet, J .
Corset, F. Froment, J . Organomet. Chem. 232 (1982) 293; p) B. M. Trost,
N. R. Schmuff, J . Am. Chem. SOC.107 (1985) 396: see also RambergBacklund reaction: L. A. Paquette, Acc. Chem. Res. I (1968) 209.
131 a) S. Wolfe, A. Rank, 1. G. Csizmadia, J . Am. Chem. Soc. 91 (1969) 1567;
b) S. Wolfe, A. Rank, L. M. Tel, I. G. Csizmadia, Chem. Commun. 1970.
96; c) A. Streitwieser Jr., lecture at the Int. Symp. Chemistry of Carbanions, Durham (UK) July 17, 1984, and a private communication (A.
Streitwieser, Jr. and D. A. Bors), April 20, 1985. We thank Prof. Streitwieser for making available to us unpublished results.
141 An X-ray structure determination of [(CH3SO2),C]’NH? was already
carried out earlier: K. Hoogsteen, Dissertation, Universitat Groningen
(Netherlands) 1957; see also P. H. Laur in A. Senning (Ed.): Sul/ur in
Organic and Inorganic Chemistry. Yo/. 3. Marcel Dekker, New York
1972, p. 235.
151 Preparation of 1 (attempt No. 56 to prepare suitable crystals): Benzylphenylsulfone (100 mg, 0.43 mmol) was dissolved in 4 mL of tetrahydrofuran (THF) and treated first with 1.2 molar equivalents of TMEDA and
then with 1.2 molar equivalents of n-butyllithium in hexane at 0°C.
After 1 h at O T , the T H F was removed at
torr and the residue dis-
0570-0833/85/0707-0574 $ 02.50/0
Angen.. Chem. h.Ed. Engl. 24 (1985) No. 7
solved in 1 mL of diethyl ether. After 16 h at 2 0 T , the yellow crystals
were freed of diethyl ether by means of a syringe, washed with 0.5 mL of
diethyl ether, and dried at
[6] D. Rogers, Acta Crysfallogr. A 3 7 (1981) 734.
[7] S. P. Patterman, I. L. Karle, G. D. Stucky, J. Am. Chem. Sac. 92 (1970)
[S] a) R. Amstutz, T. Laube, W. B. Schweizer, D. Seebach, J. D. Dunitz,
Helv. Chim. Arta 67 (1984) 224; b) R. Amstutz, J. D. Dunitz, D. Seebach,
Angew. Chem. 93 (1981) 487; Angew. Chem. lnf. Ed. Engl. 20 (1981)
[9] Cambridge Crystallographic Data Base updating 7/84. Cambridge Crystallographic Data Centre, University Chemical Laboratory, Cambridge,
England. We thank Dr. W.Mossa for the search.
[lo] a) D. R. Johnson, F. X. Powell, W. H. Kirchhoff, J. Mol. Spectrosr. 39
(1971) 136: b) J. W. C. Johns, W. B. Olson, ihid. 39 (1971) 479; c) M. E.
Jacox, D. E. Milligan, ihid. 58 (1975) 142.
[ l l ] Since we could not locate the H atom on C(1) with sufficient accuracy,
only a suitable substitution would allow a definitive statement to be
made regarding the configuration of this C atom.
thylformamide). In this system, no complications arise due
to formation of the complex [Mg(l5C5)(DMF)I2+.
The kinetic studies can be performed particularly advantageously with the DNMR method, using the HCO proton
absorption of DMF: this absorption is shifted downfield
by 0.17 ppm upon coordination of DMF to the Mg complex. As shown in Figure 2, the reciprocal residence time
Solvent Exchange on
Magnesium(Il5]Crown-5) Cornplexesa First- and Second-Order Reaction**
By Franz L. Dickert* and Manfred F. Waidhas
Dedicated to Professor Helmut Behrens on the occasion of
his 70th birthday
Solvent molecules (S) in the first coordination sphere of
metal ions M2+ can be distinguished from the free solvent
by NMR spectroscopy."] The use of DNMR, in particular,
allows the dynamics of the exchange process to be studied:
+ S* +[M(S)5S*l2' + S
Variations in temperature and pressure indicate, in
terms of activation entropy1'] and activation volume,121
this reaction has mainly dissociative character. In order to
study the mechanism of Eq. (I), it would be desirable, in
addition, to vary the concentration of the solvent molecule
(S). The limited solubility of solvated metal ions in noncoordinating cosolvents, such as CH3N02and CH2C12,can
be overcome by the use of crown ethers to make the metal
ions hydrophobic. Thus, [15]crown-5 (15C5) forms 1 :1
complexes131with metal ions M2+, in which, in addition to
the macrocycle, two solvent molecules are coordinated in
trans positions141(Fig. 1). The investigations of the mobility
of the solvent molecules described here were carried out
on the complex [Mg(15C5)(DMF)2](C104)z(DMF = dime-
Fig. 2. Reciprocal residence times I / T , 0 1 DMI-, coordinated in the complex
as a function of the concentration of free DMF
in CD3N02at 40°C.
l/z, of the DMF molecules in the first coordination sphere
of the magnesium ion increases with increasing concentration of the uncoordinated DMF in CD3N02/DMF mixtures and finally reaches a plateau value. In order to interpret this result, Equation (1) must be modified. The solvated and hydrophobic ion [Mg(15C5)(DMF)2]2+forms an
aggregate with free DMF in the inert solvent CD3N02.
However, the displacement of DMF from the first coordination sphere of the magnesium ionL5][Eq. (2)] is rate-determining:
[Mg(15C5)(DMF)z]Z+ DMF*
Kn 11
[Mg(15CS)(DMF),]2+. . .DMF*
k, Ilk,
[Mg(15C5)(DMF)(DMF*)]2+ . .. D M F
KO 11
The life-times z, for the coordinated DMF molecules are
obtainable directly from the NMR spectra and can be deis the concentration of free DMF,
scribed by Eq. (3);16' e D M F
which is bound neither in the complex [Mg(15C5)(DMF)2]2+
. 'DMF:
nor in the aggregate [Mg(15C5)(DMF)2]z+~
Fig. I . Structure 0 1 [Mg([lS]~rown-5)(DMF)~]~+;
the fluctuational crown
ether [3] is indicated by the two ellipses.
[*] Prof. Dr. F. L. Dickert, DipLChem. M. F. Waidhas
Institut fur Physikalische und Theoretische Chemie
der Universitat Erlangen-Niimberg
Egerlandstrasse 3, D-8520 Erlangen (FRG)
[**I Thi5 work was supported by the Fonds der Chemischen Industrie and
the Deutsche Forschungsgemeinschaft.
Angew. Chem. In,. Ed. Engl. 24 (1985) No. 7
k , .Ko.cDMF
The experimental results in Figure 2 can be explained by
the reaction scheme in Eq. (2) using Eq. (3). For high concentrations of DMF ( c D M F . K 0l),
% a first-order rate constant ( k , ) is obtained, which is characteristic for the solvent
exchange process in a coordinating solvent. From this kinetic viewpoint, the solution of 0.5 M [Mg(15C5)(DMF),12+
and 0 . 8 ~DMF in CD3N02 already behaves remarkably
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benzyllithium, structure, уcarbanionф, tetramethylethylenediamine, determination, phenylsulfonyl, chirality, sulfonyl, ray
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