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Extremely Long-Range 2H Isotope Effects on the Chemical Shifts in the 13C-NMR Spectra of Compounds with Conjugated Double Bonds.

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4,4-dicyano-2-(diethoxymethylene)-3-butenoate5C (Table
1,5-Dimethylverdazyls, 5 , are apparently the first hydrazyl derivatives[61in which a nonplanar substituent arrangement at the tricoordinate nitrogen has been detected experimentally. This nonplanarity is largely cancelled, not
only by aryl substituents (CH,+C6H5) but also by electron
acceptor bridges [ x H 2 - + 3 = S(4); > C H 2 - + 3 = 0 ] [ " .
1).
Table 1 (in part). Data for the compounds 3, 6A, and 5C.
3: B.p.=82"C/O.O5 t o n ; IR (film): 1905 cm-' (C=C=C); 'H-NMR (60
MHz, CDCII): 6 = 1.32 (t, 12H, CHI), 3.80 (9, 8H, OCH2); "C-NMR (25.15
MHz, CDC13): 6=13.89 (4CH3), 63.70 (4CH9, 115.15 (=C), 148.12 (2
=C(0)2)
6 A : B.p.=81 "C/O.l torr; IR (film): 2142 cm-' ( = G O ) ; 'H-NMR: 6 = 1.30
(t, 6H, CHI), 4.28 (q, 4H, OCH2); "C-NMR: 6 = 14.35 (2 CHs), 48.26 (=C),
61.34 (2 CHz), 161.05 (0-C=O), 184.59 (C=O)
5 C : B.p.= 125"C/0.05 torr; IR (film): 2220 cm-' (CN), 1700 cm-' (C=O);
'H-NMR: 6 = 1.32 (t, 3H, CH3), 1.45 (t, 6H, 2 coinciding CH,), 4.23 (q, 2H,
OCH2), 4.43 (9. 4H, 2 coinciding OCH2)
Received: December 8, 1982;
revised: January 26, 1983 [Z 218 IE]
German version: Angew. Chem. 95 (1983) 329
The complete manuscript of this communication appears in:
Angew. Chem. Suppl. 1983. 457-462
[4] F. A. Neugebauer, Angew. Chem. 85 (1973) 485; Angew. Chem. Inl. Ed.
Engl. I2 (1973) 455; F. A. Neugebauer, H. Fischer, ibid. 92 (1980) 766; 19
(1980) 724; 2. Nufurforsch. B 35 (1980) 250.
[S] Corresponding C-centered radicals, e.g. CH3CF2:K. S. Chen, J. K. Kochi, J. Am. Chem. SOC.96 (1974) 794.
[6] FornonplanarbicyclichydrazineradicalcationsseeS. F. Nelsen,G. R. Weisman, P. J. Hintz, D. Olp, M. R. Fahey, J . Chem. SOC.96 (1974) 2916.
If, as in compounds 4Da-d, Z is not a leaving group,
then reaction with 3 with elimination of ethyl chloride initially furnishes the intermediates 5Da-d, which subsequently undergo intramolecular ring closure and renewed
loss of ethyl chloride, with formation of the lactones 7ad['O1. As exemplified by the synthesis of diethyl 1J-dihydro-3-oxo-2-isobenzofuranylidenemalonate7d, 2,3-annelated 4-alkylidene-2-buten-4-olidesshould be generally accessible via analogous reactions.
Tetraethoxyallene:
Equivalent of the Fictive Malonic Ester DianionA Versatile Synthetic Building Block**
Received: November 26, 1982;
revised: January 24, 1983 [ Z 211 IE]
German version: Angew. Chem. 95 (1983) 328
The complete version of this communication appears in:
Angew. Chem. Suppl. 1983. 451-456
By Rolf W. Saalfrank* and Walter Rost
Donor/acceptor-substituted allenes are ambiphilic, and
react at the central atom (C-2) with both nucleophiles and
electrophiles"'. Correspondingly, it is predicted that 1,3donor/donor-substituted allenes have dinucleophilic properties.
We have now employed tetraethoxyallene 3r2*51
(Table 1)
as an equivalent for the fictive malonic ester dianion. As
expected, 3 reacts with phosgene 4A or thiophosgene 4B
(2= good leaving group) with elimination of two moles of
ethyl chloride (per mol 3) to give bis(ethoxycarbony1)ketene 6A (Table 1) and bis(ethoxycarbony1)thioketene 6B,
via the non-isolable intermediates 5A and 5B, respectively. 6B spontaneously dimerizes to 1,3-dithietane-2,4-diylidenebis(ma1onic acid diethyl ester).
4D/5D/7 a
[I] R. W. Saalfrank, W. Paul, H. Liebenow, Angew. Chem. 92 (1980) 740;
Angew. Chem. Int. Ed. Engl. 19 (1980) 713.
[2] Tetraethoxyallene 3 is prepared from tetraethoxyethylene using the procedure given for tetramethoxyallene.
[5] For the PE spectrum of 3 cf. R. Gleiter, R. W. Saalfrank, W. Paul, D. 0.
Cowan, M. Eckert-Maksic, Chem. Ber. 116 (1983) in press.
.[8] For the analogy of the structural elements O/C(CN)2 cf. K. Wallenfels,
K. Friedrich, J. Rieser, W. Ertel, H. K. Thieme, Angew. Chem. 88 (1976)
311; Angew. Chem. I n f . Ed. Engl. 15 (1976) 261; L. M. Doane, A. J. Fatiadi, ibid. 94 (1982) 649 and 21 (1982) 635.
[lo] Regarding 4-ylidenebutenolides cf. R. W. Saalfrank, P. Schierling,
Chem. Ber. 116 (1983), in press.
b
C
d
Table 1. *H Isotope effects on the I3C chemical shifts of compounds 1-5.
Compound
1
2
3
__
4
5
C atoms; M-values [ppb] [a]
6
7
8
9
10
11
12
11
Me
-3
8
- 10
0
7
- 9
10
4
- 8
15
6
- 9
10
0
0
-2
0
3
0
0
0
2
0
0
0
0
0
2
0
__
[a] Positive sign indicates a shift to high field of the signals of the deuterated compound relative to those of non-deuterated. Spectra were recorded in 12H6]acetone
at 100.6 MHz using a Bruker WH-400 spectrometer; in each case cu. 2 : 1 mixtures of deuterated and non-deuterated compounds were used. The spectral width was
limited to a minimum in order to collect a large number of data points and hence achieve a high precision. Assignment of the signals follows by standard methods
and for difficult cases was verified using the 2D-INADEQUATE technique. Errors amount to 0.5 ppb.
addition to the isotopic perturbation of equilibria”] there is
considerable interest on the influence of deuterium on nUnder discussion are the mechanisms of interaction which have been invoked to clarify the isotope
shifts[41.According to the Born-Oppenheimer approximation, a deuterium substituted molecule has the same electronic properties as an unsubstituted one; all differences in the
NMR data should therefore originate from different zero
point vibrations. This model predicts positive signs for
most isotope effects, i. e. a shift to high fieId. Some authors
presume an “isotope-induced” inductive effect, whereas
others correlate long-range isotope effects with the reduced capacity of deuterium to undergo hyperconjugation,
although strictly speaking this is a violation of the BornOppenheimer approximationfs1.
We have prepared the compounds 1-5 (Table l), which
allow the observation of the ’H isotope effects on the 13C
chemical shifts of conjugated C = C bonds arranged in
long chains. As shown in Table 1, extremely long-range
deuterium effects (over 12 bonds in 5 ) occur together with
a change of sign of the isotope effect at certain sites.
The ethene bridge in 3, the ethyne bridge in 4, and the
butadiene bridge in 5 are polarized as if the deuterium
were a “real” substituent with different electronic properties than hydrogen. Here, hyperconjugation cannot be the
reason, since ’H is bonded directly to an aryl moiety. The
results question the general validity of the so far discussed
mechanism of NMR isotope effects.
Received: November 3, 1982 [Z 194 IE]
German version: Angew. Chem. 55 (1983) 321
[I] P. E. Hansen, Annu. Rep. N M R Specfrosc., in press.
[2] G. Maier, H. 0. Kalinowski, K. Euler, Angew. Chem. 54 (1982) 706; Angew. Chem. Inf. Ed. Engl. 21 (1982) 693.
131 S. Berger, H. Kiinzer, Tefruhedron, in press.
141 a) E. A. Halevi, M. Nussim, A. Ron, J. Chem. SOC.1963, 866; b) E. A.
Halevi, Prog. Phys. Org. Chem. I (1963) 109; c) C. J. Jameson, Bull.
Mugn. Res. 3 (1981) 3 .
[SJ a) J. R. Wesener, H. Giinther, Tefruhedron Left. 23 (1982) 2845; b) L.
Ernst, S. Eltamany, H. Hopf, J. Am. Chem. SOC.104 (1982) 299.
322
0 Verlug Chemie GmbH, 6940 Weinheim. 1983
Electromicrobial Reduction Using Yeasts* *
By Helmut Gunther, Cornelia Frank,
Hans-Jiirgen Schuetz, Johann Bader, and Helmut Simon *
Aerobic and facultative aerobic microorganisms, particularly yeasts, have been used for decades to obtain chiral
compounds by stereospecific reduction of substituted unsaturated compounds“1. In this connection, two types of
reaction are distinguished [eqs. (a) and (b)].
We have previously indicated the principal disadvantages of such method^'^.'^. In the anaerobic mode using
yeast and glucose as electron donor, per mol of NADH
1 mol acetaldehyde is formed, which is then preferentially
reduced consuming NADH ; in the aerobic mode a considerable amount of the NADH formed as intermediate is
reoxidized in the respiration chain. The desired reaction
therefore always occurs as a side reaction.
R’\
/C=X
R2
+
yeast
2 [HI
Glucose
a
X = 0, C:
R’,
H-C-X-H
R2/
( a , b = a r b i t a r y residues)
b
X(Cab)X
x=
+
yeast
2 [HI
C H O , COOQ,
H2X(Cab)X
Glucose
:c=c:
etc.
[*I Prof. Dr. H. Simon, Dr. H. Giinther, C. Frank, Dr. H.-J. Schuetz,
[**I
J. Bader
Lehrstuhl fur Organische Chemie und Biochemie
der Technischen Universitat Miinchen
Lichtenbergstrasse 4, D-8046 Garching (Germany)
This work was supported by the Deutsche Forschungsgemeinschaft
(Sonderforschungsbereich 145) and the Fonds der Chemischen Industrie.
0570-0833/83/0404-0322 $02.50/0
Angew. Chem. Int. Ed. Engl. 22 (1983) No. 4
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bond, compounds, 13c, long, ranger, double, shifts, isotopes, effect, extremely, chemical, nmr, conjugate, spectral
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