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Lithiodiphenylmethylisocyanide-(Ч)-sparteinebis(tetrahydrofuran) Crystal Structure of a Lithiated Isocyanide.

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the H,O signal is detected. This suggests that the proton
exchange between the TMEDA nitrogen and the H,O oxygen atoms is rapid in solution.
Lithiodiphenylmethylsocy anide-( - )-sparteinebis(tetrahydr0furan): Crystal Structure of a
Lithiated Isocyanide**
Experimental Procedure
By Burkhard Ledig, Michael Marsch, Klaus Harms.
and Gernot Boche*
To a solution of428 mg (6.48 mmol) malonodinitrile in 35 mL T HF at - 78 "C
was added dropwise 4.06 mL (6.5 mmol) 1.6 M nBuLi in hexane. While the
mixture was warmed to - 50 'C and stirred for ca. 2 h, a precipitate (occasionally a brownish oil) formed. This dissolved on further addition of 10 mL THF,
4 mL (26.5 mmol) TMEDA, and (in particular) 0.6 mL (33 mmol) water. After
stirring for 12 h at room temperature the mixture was filtered. The filtrate was
concentrated under reduced pressure to one-third of its original volume. This
solution was filtered and cooled to - 18 "C. Colorless needles of 1formed, were
washed with ether, and dried in vacuo. Yield: 500 mg (37%). Single crystals
were obtained by recrystallization in a 2: 1 THF/diethyl ether mixture at 5 "C.
Correct C, H, N analyses.
'H NMR (400 MHz, [DJ-THF, 25 "C): 6 = 3.92 ( s , 2H, H,O), 2.33 (s, 4 H ,
CH, (TMEDA)), 2.17 (s, 12H, CH,, (TMEDA)), 1.35 (s, 1 H, CH). ',C NMR
(100.6 MHz. [D,I-THE 25 'C): S =131.7 (CN), 58.5 (CH, (TMEDA)), 46.1
(CH, (TMEDA)). -1.5 (CH). IR(KBr) C[cm-'] = 2190m. 2130m, 2100m
(CN).
Received: July 24, 1991 [Z 4821 IE]
German version: Angew Chem. 1992, 104. 78
CAS Registry numbers:
1. 137516-88-2; [LICH(CN)~.H,O],,137516-87-1; CH,(CN),, 109-77-3
[l] a) D. Barr, P. R. Raithhy, P. von R. Schleyer, R. Snaith, D. S. Wright, J.
Chem. Soc. Chem. Commun. 1990,643; b) D. R. Armstrong, D. Barr, P. R.
Raithby, P. von R. Schleyer, R. Snaith, D. S. Wright, Inorg. Chim. Acto
1991, f85, 163; c)P. Mukulcik, P. R. Raithby, R. Snaith, D. S. Wright,
Angen. Chrm. 1991, 103,452; Angew. Chem. lnt. Ed. Engl. 1991,30,428;
d) An example of an ethanol-complexed Li-nitronate: K. Klebe, K. H.
Bohn. M. Marsch, G. Boche, ibid. 1987, 99, 62 and 1987, 26, 78.
[2] a) K. Jens, J. Kopf, N. P. Lorenzen, E. Weiss, Chem. Ber. 1988, 121, 1201;
b) G. Boche. M. Marsch, K. Harms, Angeiv. Chem. 1986,98,373; Angew.
(%em Inr. Ed. Engl. 1986, 25, 373; c) W. Zarges, M. Marsch, K. Harms,
G. Boche, ibrd. 1989, 101, 1424; d) G. Boche, K. Harms. M. Marsch, J.
Am. Chem. S o < . 1988, 110,6925; e) W. Zarges, M. Marsch, K. Harms, G.
Boche. Chrm. Ber. 1989, 122, 1307; f) G. Boche, Angew. Chem. 1989, 101,
286; Angew. Chcm. Inr. Ed. Engl. 1989,28,277; g) W. Hiller, G. Boche, W.
Zarges. K. Harms, M. Marsch. R. Wollert, K. Dehnicke, Chem. Ber., in
press.
[3] J. Fatiadi, Synthesis 1978, 165, 241.
[4] F. G. Bordwell. Acc. Chem. Res. 1988. 21, 456.
(51 An aggregation state of less than 10 monomer units of 1 in solution is
supported by spin lattice relaxation time measurements made by "C
NMR spectroscopy.
[6] Crystal data: C,H,,LiN,O, M = 206.2, monoclinic, space group P2,/c,
~ = 8 . 2 9 2 ( 2 ) , b =34.086(3), ~=11.315(2)& /3=104.55(3)", V =
1279.2(5)A3, Z = 4, e,,,, =1.071 M ~ J I - 4393
~ , collected (8.0' < 20 <
55.0 ), 2925 independent, and 2094 observed reflections ( F 2 3 . 0 ~( F ) ) ,
212 refined parameters, R = 0.053. n R = 0.045; alldata werecollected on
a Siemens-Stoe AED diffractometer at 153 K with Mo,, (2 = 0.71073 A)
radiation. The structure was solved by direct methods (SHELXTL PLUS).
All nonhydrogen atoms were refined anisotropically, the hydrogen atoms
isotropically except H l a and H 2a which were refined with fixed isotropic
U values and restrained N-H distances (85.0 pm). Further details of the
crystal structure investigation are available on request from the Fachinformationszentrum Karlsruhe, Gesellschaft fur wissenschdfthch-technische
Information mbH, D-W-7514 Eggenstein-Leopoldshdfen 2 (FRG), on
quoting the depository number CSD-55645, the names of the authors, and
the journal citation.
[7] L. H Jones, J. Cbem. Phys. 1954, 22, 217.
[8] N. B Colthup. L. H. Daly. S. E. Wiberly. Inrroducrion ro Infrared and
Raman Spectroscopy. Academic Press, New York, 1964, p. 281-282.
[9] a) E. Kaufmann, J. Gose, P. von R. Schleyer, OrganomeraNics 1989. 8,
2577; b) C . Lambert, P. von R. Schleyer, unpublished.
[lo] a) W N. Setzer, P. von R. Schleyer, Adv. Organomet. Cbem. 1985,24,353;
h) K . Gregory. P. von R. Schleyer, R. Snaith, Adv. Inorg. Chem., in press.
[Ill E. Hirota. Y. Morino, Bull. Chem. Soc. Jpn. 1960, 33, 705.
(121 a ) N. W. Alcock, Acta Crystallogr. Sect. B 1971, 27, 1682; b) S. Chomnilpan. R. Liminga. R. Tellgren, ibid. 1977, 33, 3954.
[13] W. Bauer. D. Seebach, Helv. Chim. Acra 1984, 67, 1972.
[I41 For descriptions of 'Li, ' H HOESY see e.g.: a) W. Bauer, T. Clark, P. von
R. Schleyer, J. Am. Chem. Soc. 1987, 109, 970; b) W. Bauer, P. von R.
Schleycr. Magn. Reson. Chem. 1988. 26, 827.
[15] C. Lambert, P. von R. Schleyer, unpublished.
Angew Chmm. Int. Ed. EngI. 31 (1992) No. 1
8
Dedicated to Professor Ulrich Schollkopf
Although lithiated isocyanides have not been systematically investigated for very IongI'I-the
isomeric lithiated
cyanides were discovered one hundred years earlier[']-their
versatility in preparative chemistry is well documented.[31
Experiments aimed at stabilizing a negative charge with an
isocydnide group showed that this stabilization is a result of
the inductive effect (field effect) of the strongly electronegative sp-hybridized N atom. A conjugative interaction is thus
negligible.r41Further verification was found in quantum mec h a n i ~ a l [and
~ * ~photoelectron
~
spectroscopical[61investigations of the H,C--NC anion and the metalated isocyanides
Li(Na,MgH)CH,-NC. These studies predicted that in the
transition from H,C-NC to H,C--NC the C-N and
N=C bond lengths change only insignificantly (Table 1) and
that the anionic C atom remains pyramidal (though with a
low inversion barrier of 2.8 kcal mol - ').
Tahle 1. Structural parameters of H,C-N=C
H,C--N=C (calculated) [5d]; r [pm], Q ["I.
H,C-NC
H,C--NC
(experimental) 171 and
r(C-N)
r(N=C)
gr HCH
gr HCN
4: CNC
142.4
143.1
116.6
115.4
109.8
109.9
109.1
107.4
180
175.8
We report here the first structural determination of an
isocyanide "anion" : lithiodiphenylmethylisocyanide-(- )sparteine-bis(tetrahydr0furan) (1 . sparteine . 2 THF). In
the crystal 1 . sparteine . 2 THF is monomeric (Fig. 1). The
Li atom is bound to C1 of the isocyanide group, to N2 and
N3 of the (-)-sparteine ligand, and to 0 1 of one THF molecule. The second THF molecule is not coordinated to Li.['l
The Nl-C1 bond of the isocyanide group (116.2(1) pm) is
almost as long as the related bond in the neutral H,C-NC
(116.6 pm, see Table 1) and somewhat longer than the
average N-C
bond in C,,,~,,,,-bonded isocyanides
(1 14.6(114.5)pm['3]) as well as the calculated bond length in
H,C--NC
(115.4pm, see Table 1). The C2-Nl bond
(137.8(9) pm) is roughly as long as the related bond in C,+bonded neutral isocyanides; the mean value calculated from
eight compounds is 139.0 pm.['3*'4JThe sp2 hybridization of
C2, which is deduced from the angle sum of C2 (360 is due
to the conjugation of the negative charge on C2 with the two
phenyl rings. The torsion angles are accordingly small (NlC2-C9-C14 -6(1) and NI-C2-C3-C4 -S(I)'). The C1-N1C2 angle (178.4(6)") shows that this unit is almost linear.
Thus, the bond lengths and angles in the C--NC moiety of
1 . sparteine . 2 THF agree well with the theoretical predictions of H,C;-NC,
and the inductive stabilization of the
negative charge is structurally proven. The pyramidal geometry about the anionic C atom and the predicted aggregation to a dimer with a Li-C-N-C-Li-C-N-C eight-membered
O),
[*I
Prof. Dr. G. Boche, Dip!.-Chem. B. Ledig, M. Marsch, Dr. K. Harms
Fachbereich Chemie der UniversitPt
Hans-Meerwein-Strasse. D-W-3550 Marburg (FRG)
[**I
This research was supported by the Fonds der Chemischen Industrie and
the Deutsche Forschungsgemeinschaft (SFB 260).
VCH VerlagsgeseNschaft mbH. W-6940 Weinheim, 1992
0570-0833/92~0lO1-0079S 3 . 5 0 i ,2510
79
a
'3
13
11
-
6
-I
1
32
31
02
34
37
35
36
Fig. 1. Crystal structure of 1 . sparteine . 2 T H F [X. 121. Important bond
lengths [pm] and angles ["I. (In the numbering of the carbon atoms in the
graphic representation the element symbol was omitted.) C2-Nl 137.8(9). N1C1 116.2(10), Cl-Lil 210(2); Lil-N2 206.5(13), Lil-N3 210.3(12), Lil-01
194(2); Lil-C1-NI 176.8(8), Cl-Nl-C2 178.4(6). Nl-C2-C9 133.6(6). Nl-C2C 3 116.0(6), C3-C2-C9 130.4(7).
ring is not observed, however, in the case of 1 . sparteine . 2
THF . This is undoubtably due to the influence of the two
phenyl substituents (instead of two H atoms) on the anionic
C atom. 1 . Sparteine . 2 THF, as the only structurally characterized metalated isocyanide, contrasts dramatically with
the large number of structurally characterized transition
metal complexes with neutral isocyanide ligands." Most of
these contain an almost linear N=C-metal arrangement,
the same as that in 1 . sparteine . 2 THF; here the N1-C1-Li1
angle is 176.8(8)'. Remarkably, the short distance between
Lil and the (nonionic!) C1 in the title molecule is only
21 O(2) pm.
Received: August 16, 1991 [Z 4873 IE]
German version: Angrw. Chem. 1992. 104, 80
CAS Registry numbers:
1 . sparteine . T H E 137595-29-0; 1 . sparteine . 2 T H E 137595-28-9, diphenylmethylisocyanide. 3128-85-6; (-)-sparteine. 90-39-1.
[l] U. Schollkopf. F. Gerhart. Angen. Chem. 1968, 80. 842-843; Angew.
Chrm. Int. Ed. Engl. 1968, 7, 805, and references therein.
[2] P. Kurtz, Metboden Org. Chem. (Houben-Weylj 4111 Ed. 1952, Band 8,
p. 349.
[3] a) U. Schollkopf, Angew. Chem. 1970,82,795-805; Angar. Chem. Int. Ed.
Engl. 1970. 9, 763; h ) U . Schollkopf, Methodrn Org. Chem. (HoubenWejlj 4th Ed. 1970, Band 13/1, p. 234; c) D. Hoppe, AngeN,. Chem. 1974,
86,878-893; Angew. Chem. Int. Ed. Engl. 1974,13,795; d) U. Schollkopf,
ibid. 1977, 89. 351-360 and 1977, 16, 339; e) U. Schollkopf, Pure Appl.
Chem. 1979,5/, 1347-1355; f) Syntheses with p-toluene sulfonyl methyl
isocyanide: A. M. van Leusen, Heferocycl. Chem. 1980. 5. 111.
[4] M . P. Periasamy. H. M. Walborsky, J. Am. Chem. Soc. 1977, 99, 26312638.
[S] a) M. H. Lien, A. C. Hopkinson. M. A. McKinney, J. Mol. Struct.
THEOCHEM 1983, 105, 37-47; b) A. C . Hopkinson, M. A. McKinney,
M. H. Lien, J Compur. Chem. 1983. 4, 513; c) D. J. Swanton, G. B. Bacskay, G. D. Willett, N. S. Hush, J. Mol. Struct. THEOCHEM 1983. 91,
313-323; d) J. Kaneti. P. von R. Schleyer. T. Clark, A. J. Kos, G. W.
Spitznagel, J. G . Andrade, J. B. Moffat, J. Am. Chrm. SOC.1986, 108.
1481 -1492.
[6] S. Moran. H . B. Ellis, Jr., D. J. DeFrees, A. D. McLean, S. E. Paulson,
G . B. Ellison. J Am. Chem. SOC.1987, 109, 6004-6010.
80
0 VCH
Vrrlu~.~~r.srll.~chufi
mbH, W-6940 Wemheim, 19Y2
[7] M. Kessler, H. Ring, R. Tramhornio, W Gordy. Phw. Rev. 1950. 79, 54.
[8] 1 . Sparteine . 2 T H F crystallizes in the monoclinic space group P 2 , .
u = 921.6(10), b = 1766.7(10), c = 1098(2) pm,
= 107.65(7)',
V=
1703(4) A', 2 = 2. p..,. = 1.127 gcm-' for M = 577.8. p = 0.498 mni-'.
A crystal (0.6 x 0.4 x 0.3 mm) was measured at 163K on an Enraf-Nonius
four-circle diffractometer with a graphite monochromator using Cu,, radiation. Of the 4606 measured reflections 4279 were unique (Rim,= 0.0533)
and 3467 observed ( F > 4u(F)). Solution (PATSEE)I9' and refinement
R = 0.0837. M.R= 0.0764;
with the SHELXTL PLUS (VMS)
nonhydrogen atoms. anisotropic: H atoms with set isotropic temperature
factors at calculated positions, 387 parameters. The high temperature factors and unusual geometry parameters arise from the disorder of the single
T H F molecule. which could not be resolved. The data were corrected with
the DIFABS program."" Further details of the crystal structure investigation may be obtained from the Fachinfonnationszentrum Karlsruhe,
Gesellschaft fiir wissenschaftlich-technischeInformation mbH, D-W-7514
Eggenstein-Leopoldshafen 2 (FRG) on quoting the depository number
CSD-320245, the names of the authors, and the journal citation.
[9] E. Egert, PATTSEE F r u p e n i Rrseurch bj. Inlegrated Pullerson und Dire<!
Methods, Universitit Gottingen 1985.
[lo] G . M. Sheldrick. SHELXTL-Plus: Siemens AnulyticulX-Roy fnsfrumenfs.
Madison (USA).
[ l l ] N. Walker. D. Stuart, Acfu Crystullogr. Secr. A 1983. 3Y. 158-166.
[12] Preparation of 1 sparteine . 2 THF:Diphenylmethylisocyanide (100 mg,
0.52 mmol) was dissolved in 1.5 mL tetrahydrofuran and treated with (-)sparteine (143.3 mg, 0.62 mrnol). The deprotonation was accomplished at
-78°withn-butyllithium in n-hexane(0.62 mmol o f a 1.6 M solution). The
reaction mixture was kept at -28' for 12 h, after which time crystals
suitable for structural analysis were removed from the solution.
[33] Cambridge Structural Data Base, Version 4.5, July 1991. F. H. Allen. 0.
Kennard, R. Taylor, Ace. Chem. Rrs. 1983, 16, 146-153.
[14] The corresponding mean obtained from 23 spz-bound isocyanides is
145.6 pm"31.
[15] a) E. Singleton, H. E. Oosthuizen, Adv. Orgunomer. Chenz. 1983,22. 209310, with references to other review articles and many original reports:
b) a more recent report: F. E. Hahn, M. Tamm. Angen. Chem. 1991, 103.
213-215; Angeir. Chem. Int. Ed. EngI. 1991, 30, 203.
Concave Wrapped Protons: Reagents for
Contra-Thermodynamic Protonations**
By Ulrich Luning* and Michael Muller
Dedicated to Pvofessor Hovst Pvinzhach on the occasion
of his 60th birthday
No widely applicable reagent for selective, and in particular stereoselective, protonations is known."] A very promising solution to this problem is offered by concave reagents,
which are standard reagents of organic chemistry built into
concave structural units.['] The class of compounds that contains pyridine rings in a concave arrangement (concave
R,CHNO,
2
R,C=NO,H
3
H,O
R,C=O
4
Scheme 1. Protonation reactions with nitronate ions 1.
[*I
Priv.-Doz. Dr. U. Liining, Dipl.-Chem. M. Miiller
Chemisches Laboratorium der Universitat
Albertstrasse 21, D-W-7800 Freihurg (FRG)
[**I Concave Reagents, Part 10. This work was supported by the Fonds der
Chemischen Industrie and the Deutsche Forschungsgemeinschaft. We
thank Prof. C. Ruchardt for his generous support. Part 9: U. Liining, R.
Baumstark, W. Schyja, Liebigs Awn Chrm. 1991, 999.
057o-O833/Y2joI01-(~080$3.50+ ,2510
Angew. Chem. Int. Ed. En$ 31 (19Y2) No. 1
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crystals, structure, tetrahydrofuran, lithiated, sparteinebis, lithiodiphenylmethylisocyanide, isocyanides
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