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Electron Density Distribution in the Bonds of the Bridged Bicyclo[1.1.0]butane System 1 5-Dimethyltricyclo[2.1.0

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[I] a) 1. Fleming: Frontier Orbitals and Organic Chemical Readions, Wiley,
London 1976: b) B. Giese, J. Meixner, Angew. Chem. 91 (1979) 167: Angew. Chem. I n t . Ed. Engl. 18 (1979) 154: c) F. Minisci, A. Citterio in G.
H. Williams: Advances in Free-Radical Chemistry. Heyden, London
[2] The terms "ionic nucleophilic addition" and "ionic nucleophile" can also
be applied to Michael additions of neutral molecules in which zwitterions
occur as intermediates.
131 1. 1. Dickstein, G. 1. Miller in S. Patai: Chemistry ofthe Carbon-Carbon
Triple Bond. Vol. 2, Wiley, New York 1978.
[4] Comparative kinetic studies of the additions of nucleophilic alkyl radicals to alkynes have previously been carried out only with acetylene and
higher alkynes: P. I. Abell in C. H. Bamford, C. F. H. Tripper: Comprehensive Chemical Kinetics, Vol. 18. Elsevier, Amsterdam 1976.
(51 a) K. N. Houk in W. A. Pryor: Frontiers of Free Radical Chemistry, Academic Press. New York 1980; CJ also K . N. Houk, R . W . Strozier. M. D .
Rozeboom. S . Nagase. J . Am. Chem. Soc. I04 (1982) 323: h) B. Giese, J.
Meixner, Tetrahedron Lett. 1977, 2783.
Reversible 02-Addition to
Polymeric Schiff-Base Complexes of V" and Mn"
and Their Use as Oxidation Catalysts
By Wolfgang Sawodny*, Reinhard Grunes, and
Helmut Reitzle
In connection with our investigations on polymeric
Schiff-base complexes"-31 we have now also been able to
synthesize such compounds with V" and Mn" as central
ion. The complexation reaction proceeds more smoothly
and productively oia a novel route involving the Na-salt as
intermediate (Scheme 1).
2 NaOCH3
- 2 CHiOH
\ X = C H 4
2 NaCl
original MI'-complexes be recovered by reduction with
N2H4.H20in CH30H, but the O2 is also liberated in a
vacuum at temperatures above 200 "C. This would suggest
that these complexes might be good catalysts for oxidation
reactions. Preliminary investigations on unsaturated hydrocarbons have shown that the polymeric V"- and Mn"Schiff-base complexes are as good as, if not even better
than, the best previously known metal complex oxidation
catalysts (Co"-salene, Fell-porphyrin c~mplexes)['~.
Table 3. Oxidation of cumene with Mn"-complex ( X = - ( C H h - ) as catalyst: concentration lo-' mol/mol cumene. Reaction time: 15 h (at 30 "C: 65
h). The difference making up 100°/o consists of small amounts of methylstyrene (< IYo) together with unidentified products.
I1 [Oh]
111 [Oh]
111 : I1
In the oxidation of cumene-addition of cumene hydroperoxide as initiator is not necessary here-only traces of
the initially formed hydroperoxide['] are found, evidence
that its decomposition is likewise catalyzed by the complex. Generally, the Mn"-complexes are more reactive
than the V"-complexes. Oxidation increases with increasing temperature, more and more acetophenone being
formed besides 2-phenyl-2-propanol ; methylstyrene is also
formed in trace amounts. The most favorable temperature
is ca. 100 "C. At higher temperatures cumene is already oxidized by O2 without catalysts. Addition of polymeric
Schiff-base metal complexes then has an inhibiting effect
on the oxidation.
Received: April 23, 1982 [Z 18 IE]
revised: July 19, 1982
German version: Angew. Chem. 94 (1982) 803
The complete manuscript of this communication appears in:
Angew. Chem. Suppl. 1982, 1662- 1669
[ I ] W. Sawodny, M. Riederer, Angew. Chem. 89 (1977) 897: Angew. Chem.
Int. Ed. Engl. 16 (1977) 859.
121 M. Riederer, E. Urban, W. Sawodny, Angew. Chem. 89 (1977) 898: Angew. Chem. Int. Ed. Engl. 16 (1977) 860.
131 W. Sawodny, M. Riederer, E. Urban, Inorg. Chim. Acta 29 (1978) 63.
(71 R. Zinburg, Dissertation, Universitat Ulm 198I .
IS] Y. Jurusu, W. Storck, G. Manecke, Makrornol. Chem. 176 (1975) 3185.
Scheme 1
Electron Density Distribution in the Bonds of
the Bridged Bicycloll.l.Olbutane System
The V"- and Mn"-complexes synthesized according to
Scheme 1 take up 0.4-0.5 mol O2 per mol of complex (determined gravimetrically) at room temperature. The formerly high magnetic moments (ca. 5.5 y, in the case of the
Mn"-complex and 4.5ye in the case of the V"-complex)
are reduced by the 02-uptake. Accordingly, the O2 is presumably incorporated as a peroxo-bridge between two metal ions. This assumption is supported by the observation
that the same oxidized complexes are also formed by direct reaction of the MI'-complexes with H202.
O2 is taken up reversibly. This is astonishing, especially
in the case of the V"-complexes. Thus, not only can the
By Herrnann Irgnartinger * and Annette Goldmann
The bond between the bridgehead atoms in the bicyclo[l.l.O]butane system is influenced by steric factors and
substituent effects"]. Its properties are considerably different from those of a normal C-C single bond. Using the
X-X method[21we have experimentally determined the
electron density distribution in the bonds of the bridged bicyclo[l.l.O]butane system 1,5-dimethyltricyclo[]pentan-3-one 1 from the X-ray data measured at - 155 "C. As
[*I Prof. Dr. W. Sawodny, R. Griines, H. Reitzle
Abteilung fur Anorganische Chemie der Universitat
Oberer Eselsberg, D-7900 Ulm (Germany)
[*I Prof. Dr. H. Irngartinger, A. Goldmann
Organisch-chemisches lnstitut der Universitat
Im Neuenheimer Feld 270, D-6900 Heidelberg (Germany)
Angew. Chem. Int. Ed. Engl. 21 (1982) No. 10
0 Verlag Chemie GmbH, 6940 Weinheim. 1982
0570-0833/82/1010-0775 $02.50/0
769- 774 Advertisement
previously found at room temperature""], the C3-C3'
bridge bond length (1.417 A, Fig. Id) is remarkably short.
plane. The electron densities of the exocyclic bonds, of the
C=O bond, of the oxygen atom exhibit no unusual
characteristics (Fig. I).
Received: May 8, 1982 [Z 56 IE]
German version: Angew. Chem. 94 (1982) 786
[ I ] a) H. Irngartinger, K. L. Lukas, Angew. Chem. 91 (1979) 750; Angew.
Chem. Int. Ed. Engl. 18 (1979) 694: b) H. Irngartinger, A. Goldmann, J.
Chem. Sac. Chem. Commun. 1981, 455.
[21 P. Coppens, Angew. Chem. 89 (1977) 33; Angew. Chem. I n [ . Ed. Engl. 16
(1977) 32.
131 P. Chakrabarti, P. Seiler, J. D. Dunitz, A.-D. Schliiter, G . Szeimies, J. Am.
Chem. SOC.
103 (I98 I ) 7378.
Facile Preparation of
N-Acyl-2-(diethoxyphosphoryl)glycine Esters and
Their Use in the Synthesis of
Dehydroamino Acid Esters**
By Ulrich Schmidt *, Albrecht Lieberknecht,
Ute Schanbacher. Thomas Beuttler, and Jochen Wild
Fig. I . Electron density distribution i n the bonds of 1 aqd bond lengths
- 155 "C. The contours are drawn at intervals of 0.05 eA-' and the standard
deviation of the bond lengths is 0.001 A. The atoms are not numbered in accordance with IUPAC rules. Crystallographic data of 1 (C,H,O): for data at
room temperature see [11; at - 155 "C: a = 10.7598(7), b=6.8256(4),
C2/c;2=4. Up tosinO/A=1.15 k ' ( M o K , radiation) 1968 independent, repeatedly measured reflections (248 of which
were unobserved, F,, <2.5a(E,)) were collected; the C and 0 atoms were refined with 1028 reflections of higher order (0.70<sinB/A< 1.15 k',
27 reflections per variable); R = 0.036. The deformation densities are based on 753
(F,,- F , ) values taken from the range sinO/k<0.7 A-'. The carbonyl group
in the molecule is located on a crystallographic twofold axis. a) Section
through the plane of atoms CI,C3,C3',C4,C4',0; b) Section through the
plane of the atoms CI,C2,C2'.0; c) Section through the plane of the three
density maxima of bonds C2-C3, C2-C3', and C3-C3'; d) Bond lengths.
A phosphorylglycine ester serves as a synthetic building
block in the syntheses of cephalosporins"'. Many methods
are known for the preparation of N-Acylphosphorylglycine esters; however, none of them are straightforward"-31. We describe an effective three-step synthesis of
these compounds, which are suitable starting materials for
preparation of dehydroamino acids; these in turn can
readily be hydrogenated to amino acids with, in many
cases, high optical induction. The route shown in Scheme
1 is, therefore, a novel synthesis of amino acids; starting
from aldehydes, amino acid esters having two additional
carbon atoms or tert-butoxycarbonylamino acid esters are
formed under mild conditions and, in contrast to almost
all other syntheses, an acid hydrolysis step is avoided.
1. XI3
2. P(OC2Hd3
1 , R- H
2 , R = C2H5
3 or 5
3 , R' = Z
4, R'= H
5 , R ' = Boc
Bo, R"CH0
6 , R" = A l k y l ,
R' = Z o r Boc
All the electron density maxima of the bonds of the tricyclopentane framwork of 1 are clearly displaced outwards from the bond axes, and hence this system consists
only of bent bonds. In contrast to a [3.l.l]propellane derivativer3l,which also contains the bicycle[ 1.1.O]butane moiety
-with, however, inverted C-atoms-the electron density
in the bridge bond C3-C3' of 1 clearly stands out, and is
displaced by approximately 0.40 A away from the bond
axis (towards the top of Fig. la). The electron density
exhibits a rotationally symmetric distribution in a section
perpendicular to the bond axis (Fig. lb); below the C3C3' bond axis it is equal to zero. Accordingly, no experimental evidence for 71 character in this bond is found, and
it can best be described as a bent o-bond. All three electron density maxima of the three-membered ring C2, C3,
$3' do not lie in the plane of the ring. The C atoms are 0.04
A (C2) above, and 0.19 (C3) and 0.18 (C3') A below the
plane through the three electron density maxima (Fig. lc).
The bonds are, therefore, not only bent within the plane of
the three-membered ring, but are also twisted out of this
0 Verlag Chemie G m b H , 6940 Weinheim. 1982
0, ,
H5C z-O-CH2C Hz-C-( CHp)5-CH-C OzC zH,
Boc = tBuOCO
Scheme I
Prof. Dr. U. Schmidt, Dr. A. Lieberknecht, U. Schanbacher,
Th. Beuttler, J. Wild
Institut fur Organische Chemie, Biochemie und Isotopenforschung
der Universitat
Pfaffenwaldring 55, D-7000 Stuttgart 80 (Germany)
[**I Amino Acids and Peptides, Part 36. Dehydroamino Acids, Part 16.Part 35: U. Schmidt, M. Dietsche, Angew. Chem. 94 (1982) 145; Angew.
Chem. I n t . Ed. Engl. 21 (1982) 143. This work was supported by the
Fonds der Chemischen lndustrie and by BASF AG; Part 15: U.
Schmidt, E. Ohler, J. Hausler, H. Poisel, Fortschr. Chem. Org. Natursf.
0570-0833/82/1010-0776 $02.50/0
Angew. Chem. Inr. Ed. Engl. 21 (1982) No. I0
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bond, distributions, bicycle, dimethyltricyclo, bridge, electro, system, butant, density
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