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The Structure of Vicinal PentaketonesЧX-Ray Structure Investigations and Calculations.

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The cation 2 undergoes a number of other interesting reactions (Scheme 2). Thus, treatment with a slight excess of
sBu,AIH (CH,C1,, -78°C) affords a 2:3 mixture of the
starting material and the
q4-buta-l ,3-diene complex 5, which could be separated by column chromatography
(A1,0, grade 11, benzene/hexane, 25 "C). This finding can be
rationalized in terms of a competitive reaction involving delivery of "H@" to the carbenoid or a-carbon of 2 and proton
abstraction from the &-carbon. In contrast, reaction of 2
(CH,CI,, -78 "C) with EtC(CH,O),P does not lead to nucleophilic attack on the cx-carbon, but instead deprotonation
occurs and the triphenylphosphane is replaced by the cage
phosphite to form (column chromatography, silica, MeCN,
-30°C) the pink solid 6.[16]
Although 2 does not react with carbon monoxide, treatment (CH,CI,/THF, - 78 "C to + 25 "C and chromatography on silica/MeCN) with a two-fold excess of the isocyanides RNC (R = 2,6-Me2C,H,, tBu) resulted in the
formation of red-orange 7and yellow 8 respectively as slightly air-sensitive solids. Compound 7 was identified as the
hexafluoroantimonate salt by comparison of the 'H-NMR
and IR spectra with those of the fluoroborate species described by Yamazaki." 71 The corresponding spectroscopic
data"'] for 8 suggested that an unexpected reaction had
occurred involving loss of the tBu substituent, and this has
now been confirmed
by single crystal X-ray crystallography. Such a fragmentation reaction has not been previously
obtained.
Received: April 2, 1990 [Z 3892 IE]
German version: Angew. Chon. 102 (1990) 1062
CAS-Registry numbers:
1, 12124-09-3;2 . SbF,, 128732-31-0;2 . CF,CO,, 128819-87-4;3. 128732.321;4,1278-02-0,5,128732-33-2; 6,128732-34-3;7, 128732-38-4;8,128732-37-6,
EtC(CH,O),P. 824-11-3; 2,6-Me2C,H,NC, 2769-71-3; tBuNC, 7188-38-7.
111 a) P. Hong, Y. ydmazdki, J. Organomel. Chem. 373 (1989) 133-142; b) H.
Bonnemann, W. Brijoux, Aspecrs Homogeneous Catal. 5 (1984) 78- 196;
c) H. Bonnemann, Angew. Chem. 97 (1985) 264; Angex. Chem. In!. Ed.
Engl. 24 (1985) 248-262; d) P. Cioni, P. Diversi, G. Ingrosso, A.
Lucherini, P. ROncd, J. Mo/. Carol. 40 (1987) 337-387, K. Jonas Angew.
Chem. 97(1985)292; Angew. Chem. Int. Ed. Engl.24(1988)295-311;f) K.
Abdulla, B. L. Booth, C. Stacey, 1 Organomet. Chem. 293 (1985) 103Dalron Trans. 1978,
114; p)Y. Wakatsukt, H. Yamazaki, J. Chem. SOC.
1278-1282; h) S. T. Flynn, S. E. Hasso-Henderson, A. W. Parkins,J Mol.
Calal. 32 (1985) 101-105; i) E. Lindner, R. M. Jansen. H. A. Mayer, W.
Hiller, R. Fawzi, OrganometaI/ics 8 (1989) 2358-2360.
121 D. R. McAllister, J. E. Bercdw, R. G. Bergman, J. Am. Chem. SOC.99
(1977) 1666- 1668.
111 (1989)
[3] F. E. Hong, C. W. Eigenbrot, T. P. Fehlner, J. Am. Chem. SOC.
949 - 956.
141 J. M. O'Connor, L. Pu, R. Uhrhdmmer, J. A. Johnson, J. Am. Chem. SOC.
I l l , (1989) 1889-1891.
[5] H. Yamazaki, N. Hagihara, J. Organome/. Chem., 7 (1967) p. 22: Bull.
Chem. SOC.Jpn. 44 (1971) 226062261,
161 2. 'H NMR (360 MHz, CD,Cl,, -20°C): 6 = 7.9-6.4 (m, 35 H. C,H,),
5.17 (s, 5H. C,H,), 3.31 (s, 1 H, CHPh); '3C(1H) NMR (90 MHz,
CD,CI,, -20°C): 6 = 176.9 [d, C., J(CP) 25.7 Hz], 143.0-128.0 (C, and
C,), 141.0- 123.0 (aryl), 90.9 (C,H,), 75.8 (C,); 3'P{'H) NMR (101 MHz,
CD,Cl,, -20°C). 6 = 35.7.
[7] a) M. Crocker, M. Green, A. G. Orpen, H. P. Neumann, C. J. Schaverien,
J. Chem. SOC.Chetn. Commun 1984, 1351-1353: b)M. Crocker, M.
Green, K. R. Nagle, A. G. Orpen, H. P. Neumann, C. E. Morton, C. J.
Schaverien, OrgonometaNirs 9 (1990) 1422-1434.
181 L. Brammer, M. Crocker, B. J. Dunne, M. Green, C. E. Morton, K. R.
Nagle, A. G Orpen, J1 Chem. SOC.Chem. Commun. 1986, 1226-1228.
[9] D. C. Brower, K. R. Birdwhistell, J. L. Templeton, 0rganometallic.r 5
(1986) 94-98.
[lo] G. C. Conole, M. Green, M. McPdrtlin, C. Reeve, C. M. Woolhouse, J.
Chem SOC.
Chem. Commrm. 1988, 1310-1313.
[11] 3: ' H N M R (360MHz. CD,CI,, -20°C): 6 = 7.9-5.4 (overlapping signals) 38H, C,H,, qZ-C,H,), 5.00 (s, 5H, C,H,), 2.96 (d, l H , CHPh,
J(HP) =2.9 Hz); ',C{'HJ NMR (90MHz, CD,CI,, -20°C): 6 =
140.3-126.1 (aryl), 99.8(s), 96.9is) (C,,C,), 88.2 (C,H,), 58.9 (C6),44.7 [d,
1048
0 VCH
Verlagsgese/lschajt mbH, 0-6940 Weinheim, 1990
C,, J(CP)
=
36.6 Hz]; ,'P{'H} NMR (101 MHz, CD,CI,,
-2OOC).
6 = 23.3.
[12] W. D. Jones. L. Dong, J. Am. Chem. Soc. 111 (1989) 8722-8723.
I131 a)W. D. Harman, H. Taube, J. Am. Chem. Soc. 110 (1988) 5403-5407;
b) W. D. Harman, M. Sekine, H. Taube, ibid. 110 (1988) 5728-8731;
c) W. D. Harman, H. Taube, ibid. I10 (1988) 7585-7887; d) K.-B. Shui,
C:C. Chou, S.-L. Wang, S.X. Wei OrganomrtnNics 9 (1990) 286-288.
1141 a) A. Nakamurd, N. Hagihara, Bull. Chem. Soc. Jpn. 34 (1961) 452-453;
b) M. D. Rausch, G. F. Westover, E. Mintz, G. M. Reisner, I. Bernal, A.
Clearfield, J M. Troup, Inorg. Chem. 18 (1979) 2608-2615.
1151 H. Yamazaki, K. Yasufuku, Y. Wakatsuki, Orgonometallies 2 (1983) 726732.
[16] 6 : 'HNMR(360 MHz,CDC13,25'C): 6 = 7.3-6.6(m, 20H,C6H,),4.88
(S, 5H, CsH,), 4.30 Id, 6H. OCH,, J(HP) = 8.2 Hz], 1.26 [q, 2H, CCH,,
J(HH1 = 7.7 Hz], 0.87 [t, 3 H, CH,, J(HH) = 7.7 Hz]; 13C{'H} NMR
(90 MHz, CDCI,, 25°C): 6 = 162.7 [d, C., Cs,, J(CP] = 18.5 Hz) 186.7.~
123.3 (aryl), 142.3 [d, C,, C,,, J(CP) = 1.3 Hzl, 89.4 (C,H,), 74.6 [d,
OCH,, J(CP) = 2.9 Hz], 35.8 [CEt, J(CP) = 11.5 Hz], 23.4 (CH,), 7.3
(CH3); 31P(1H}NMR (101 MHz, CDCI,, 25°C): 6 = 143.5.
[17] H. Yamazaki, Y. Wakatsuki, Bull. Chem. Soc. Jpn. 52 (1979) 1239-1240.
[I81 8: 'H N MR (360MHz, CD,CI,, 25'C): 6 = 7.6-6.9 (m, 20H, C6H,),
8.39 (s, SH, C,H,), 4.76 (bs, 2H, NH,); "CC('H} NMR (90MHz.
CD,CI,. 25°C): 6 = 131.9-128.2 (aryl), 122.7 (C-NH,), 96.2 (Cm,Cz.),
88.1 (C,H,). 84.0 (CD,Cp,),:IR: v,,(cm-')(CH,CI,) 3474 m, 3381 m.
1191 S. C. Nyburg, A. W. Parkins, M. Green, unpublished.
The Structure of Vicinal Pentaketones-X-Ray
Structure Investigations and Calculations **
By Rolf Gleiter,* Edwin Litterst, Thomas Oeser,
and Hermann Irngartinger *
Dedicated to Professor Tetsuo Nozoe
on the occasion of his 88th birthday
The recently prepared vicinal pentaketones ['I are ideally
suited as models for describing the electronic and steric requirements of a keto group. Each CO moiety possesses a
strong local dipole moment and provides two lone pairs at
the oxygen as well as a n- and a n*-orbital. So far, only a few
structural data on open chain vicinal di-,I21 tri-13*4]and
tetraketones 41 are available. Empirical calculations
(MM2ts1)predict the dihedral angles of cc-diketones[61and
triketones but fail to do so for those of tetra- and pentaketones. Older semiempirical
as well as more
recent ones['] and ab initio calculations with a minimal basis
(STO 3G)J91 give unsatisfactory results with respect to the
torsional angles of vicinal CO groups in po1yketones.f'' In
this communication we report on the structural parameters
of vicinal pentaketones and present a simple model which
reproduces the torsional angles properly.
C33
OCO-CO-CO-CO-CO-R
I, R = /Bu; 2, R = Ph
In Figure 1 we show the conformation and most signifiAn
cant bond lengths of tert-butylphenylpentaketone (1).[lo1
X-ray investigation on single crystals of diphenylpentake[*] Prof. Dr. R. Gleiter, Prof. Dr. H. Irngartinger, Dr. E. Litterst,
Dipl. Chem. T. Oeser
Organisch-Chemisches Institut der Universitat
Im Neuenheimer Feld 270, D-6900 Heidelberg (FRG)
[**I This work was supported by the Deutsche Forschungsgemeinschaft, the
Fonds der Chemischen Industrie, the German-Israeli Foundation for
Scientific Research and Development, and the BASF Aktiengesellschaft.
We are grateful to Frau U. Huber-Patz, Frau U. Wiesinger, Herrn S. Gries
and Herrn U. Reifenstahl for experimental help.
0570-0833~90jO909-iO48
$3.50+ .25/0
Angew. Chem. Int. Ed. Engl. 29 (1990) No. 9
tion of 2 gives exclusively 3,5-dihydroxy-2,6-diphenyl-4Hpyran-4-one (3).11'1
1 -H,O
Fig. I . Structure of I In the crystal, with bond lengths (standard deviations
0.002 to 0.003 A).
tone (2)"O1 yielded similar torsional angles and bond lengths
(see Table I ) as for 1. In both cases the three central CO
groups are arranged cisoid to each other while the outer ones
Table I . Most relevant bond lengths of 2 [A]
~~
C1-C6
1.459(3)
C1-01
1.215(2)
CI-C2
1.529(4)
C2-02
1 204(2)
C2-C3
1.522(3)
C3-03
1.1960)
C3-C4
1.530(3)
C404
1.195(2)
C&CS
1 533(3)
CS-05
1.219(2)
C5-Cl2
1.467(3)
3
On applying current force field methods to calculate the
torsional angles between the CO groups by assuming the
usual dipole-dipole forces as well as torsional and van der
Waals forces, we were unable to reproduce the geometry of
the pentaketones satisfactorily. However, upon neglecting
torsional and van der Waals forces, assuming the dipole moment of each CO group to be 2.3 D,Isblthe bond distances
between the adjacent carbon atoms to be fixed at 1.54 A, and
those between C and 0 at 1.20 A, as well as bond angles of
120", we were able to reproduce the torsional angles between
CO groups of vicinal polyketones. The minima found on the
corresponding hypersurface show remarkable agreement
with experimental data: For 1,2-diketones a dihedral angle
of 180" results, for 1,2,3-triketones both dihedral angles are
127". For vicinal tetraketones we find one broad minimum
with two trans 1,2-diketone units (a, z 180°, x2 z 90",
a, z 180"). A helical structure with a I z a2 z Y, z 130" also
fits well into this minimum.
In Figure 2 we show the dipole-energy of a vicinal pentaketone as a function of a, and a,. For each point of the
n
A
show a transoid conformation. The recorded torsional angles for 1 and 2 are given in Table 2.
It is interesting to note that the distances between 0 5 and
C1 and C2 are relatively short (see Table 2). This interaction
leads to a slight pyramidalization of the keto groups at C1
and C2. The deviation of C1 and C2 in 1 and 2 from the plane
defined by its three neighbor atoms amounts to 0.014&
0.063 A in 1 and 0.006 Al0.064 8, in 2. This deviation occurs
360
Fig. 2. Dipole energy hypersurface for five vicinal C 0 groups as a function of
x2 and a,.
xQJ
0
'
I&
' 0
Scheme 1. Definition of the torsional angles in Table 2
Table 2. Torsional angles a I"] between the CO groups of 1 and 2 and selected
distances [A] between 0 1 . 0 5 and carbon centers. For the definition of a, -x4
see Scheme 1.
1 158.4 -52.1
2 155.8 -55.4
-11.4
-30.7
172.9 2.738(2)
-151.0 2.775(3)
2.578(2)
2.519(3)
2.953(2) 3.195(2)
3.036(3) 3.587(3)
in the direction of 0 5 . Corresponding changes at the other
side of the molecule cannot be detected since the C . . 0
distances are larger (see Table 2). The proximity of the terminal CO groups is also in line with the finding that the reducAngen. Chrm. i n [ . Ed. Engl. 29 (1990) No. 9
surface the energy was minimized for a, and a4. The surface
is symmetrical with respect to the diagonal a2 = a,. Two
nearly equal minima are found at B (a, z a, NN 25",
a , z 180", a4 N 180") at 20.9 kcal mol-' and at A
(a,
a, z 129", a, NN a4 N 140") at 20.0 kcal mol-'. Minimum B corresponds to the structures found for 1 and 2. An
analysis of the interactions between the CO groups in B
shows that the unfavorable cisoid arrangement of the central
(CO), unit allows the peripheral CO groups to come into a
conformation so that their dipole moments are nearly compensated (see Fig. 1). Semiempirical calculations on I and 2
suggest an electron transfer from the lone pairs at 0 5 and--to a lesser extent-from 0 1 to the a* level. A further stabilization of minimum B with respect to A, which is not included in our simple model, is due to the better overlap between
the CO groups in B. Our simple model suggests that the
dipole moment determines the conformation of the (CO),
moiety. In the current force fields the interplay between torsional, van der Waals and dipole-dipole forces of CO groups
is not treated properly.
Q VCH Verlagsgesellschafr mbH. D-6940 Wernheim, 1990
0570-0833/90/0909-i0493 3.50+ .25/0
1049
Experimental
The synthesis of 1 was carried out analogously to that of 2 [l] 1: ' H N M R
(200 MHz, CDCI,): 6 = 7.9-8.0 (m, 2H), 6.8-7.15 (m, 3H), 1.15 (s, 9H); "C
N M R (66, MHZ, CDCI,): 6 = 205.6 (s), 191.0 (s), 189.1 (s), 183.3 (s), 182.7 (s),
136 7(d), 131.8(~),131.3(d), 129.9(d),43.5(~),25.8(q),IR(CH,CI,).P= 3148
( E,
) : 431 (207). 542
(w), 1728 (s), 1664 (s). 1594 (s) cm-'; UV (CH,CI,): i.,,
(136) nm.
The reduction of 2 (hydrate) was carried out with PtOJH, in ethanol at room
temperature (32% yield) or in ethanollwater (3: I ) with L-ascorbinic acid (55 %
yield). 3 . m.p. 249°C; IR (cm-'). C 3250 (br), 1572 (s). 1390 (s); ' H N M R
(300MHz. d,THF): 6 = 7.37-7.56 (6H, m), 8.,2-8.7 (4H, m), 8.93 (2H. br);
" C N M R (200 MHz, [D,]DMSO): b = 126.97 (d), 128.59 (d), 129.34 (d),
131.35 (s), 140.96 (s), 144.44(s), 169.45 (s). The structure o f 3 wasconfirmed by
an X-ray investigation on the 3,5-bisacetyl-derivativeof 3.1111
munoglobulins and transferrin, carry functionalities important for biological selectivity.['] As a rule, N-glycoproteins
are characterized by an N-glycosidic bond between an Nacetylglucosamine unit and the arnide function of an asparagine unit. On the carbohydrate side there follow a further N-acetylglucosamine unit and a mannose unit as
building blocks. The linkages are p(1 -4) glycosidic, so that
this section of the core region and binding region has the
structure ManPl + 4GlcNAcpI + 4GlcNacpl +Asn 1.
-NH- CH-
CO-
I
CH,
Received: March 14, 1990 [ Z 3857 IE]
German version: Angew. Chem. 102 (1990) 1071
1
CAS-Registry numbers:
1, 128731-90-8; 2, 104779-80-8; 3, 128731-91-9
HO
AcNH
OH
[l] R. Gleiter, G. Krennrich, M. Langer, Angew, Chem. 98 (1986) 1019;
Angew. Chem. Int Ed. Engl. 25 (1986) 999.
[2] C. J. Brown, R. Sadanaga Acta Crystallogr. 18 (1965) 158; E. J. Gabe, Y.
Le Page, F. L. Lee, L. R. C. Barclay, Acfa Crystallogr. Seer. B37 (1981)
197; K. Eriks. T. D. Hayden, S Hsi Yang, I. Y.Chan, J. Am Chem. Soc.
105 (1983) 3940.
[3] M. B. Rubin, Chem. Rev. 75 (1975) 177.
[4] R. L. Beddoes. 1. R. Cannon. M. Heller, 0. S. Mills, V. A. Patrick. M. B.
Rubin, A. H. White, Aust. J. Chem. 35 (1982) 543; M. Kaftory, M. B.
Rubin, J. Chem. Soc. Perkin Fans. 2 1983, 149
151 a ) U . Burkert, N. L. Allhger: Molecular Mechanirs ( A C S Monogr. 177,
(1982)): b) MMX: consistent of the routines MM2 + MMPI[5a], written
by J. J. Gajewski, K. E. Gilbert, Serena Software, Bloomington, IN, USA.
[6] R. Isaksson. T. Liljefors, J Chem. Soc. Perkin Trans. 11,(1983) 1351.
[7] J. Kroner, W. Strack, Angeiv. Chem. 84 (1972) 210; Angew. Chem. Int. E d
Enxl. 11 (1972) 220; S. Wolfe. J. E. Berry, M. R. Peterson, Cun. J Chc,m.
54 (1976) 210.
[S] E. Litterst, Dissertation, UniversitPt Heidelberg, 1990.
[9] W. J. Hehre, L. Radom, P. von R. Schleyer, J. A. Pople: A b initlo Molecular Orbital Theory, Wiley, New York 1986.
[lo] 1. u = 6.347(1), b = 10.175(3). c = 11.686(2)& a = 111.41(1), fi =
93.90(1). y = 95.46(2)", v = 695.1(5) [ A 9 , z = 2, space group Pi,crystal
size 0.5 x 0.35 x 0.4 [mm3]. independent reflexions 3337, observed 2072
( I 2 2.5a(o], R / R , = 0.038/0.049 (W = ~ / o ( F =
~ )(4~x F ~ ) / o ( F ~ )-2:
').
a = 19.187(5), b = 8.880(2), c = 18.582 A, a = 9 0 . p = 117 06(3).,
7 = 90", V = 2819.4 (3) [A'], 2 = 8, space group C2ic. crystal size
0.5 x 0.45 x 0.3 [mm'], independent reflexions: 3373, observed 1325
( I 2 2,50(/)), R / R , = 0.038/0.042 (K= l/o(F;) = (4 x F:)/o(F@').-The
data were collected on an automatic diffractometer (CAD4- Enraf Nonius, MoKeradiation, graphite monochromater, w - 20 scan). The structures were solved by direct methods and refined by full matrix procedure
(anisotropic thermal parameters for C and 0, positions of the H atoms
localized according to difference Fourier synthesis and isotropically refined) A final difference Fourier map revealed no peaks greater than 0.17
e/A' (1) and 0.19 e/A' for 2. Further details of the crystal structure investigations are available on request from the Fachinformationszentrum
Energie, Physik, Mathematik GmbH, D-7514 Eggenstein-Leopoldshafen
2 (FRG). on quoting the depository number CSD 54658, the names of the
authors and the journal citation.
M. Langer, Di.?.serfu/ion.Universitdt Heidelberg, 1987.
The P-glycosidically linked mannose unit in 1 is a central
element in the oligosaccharide side chains of the N-glycoproteins, since it is the starting point of branching in the
antennary saccharide side chains via binding of a-mannoside
units.
The especially difficult synthesis of P-mannosides (neighboring group participation and thermodynamic control
strongly favor the formation of a-mannosides) was effectively achieved by use of silver silicate catalysts121o r via oxidation/reduction at the C-2 center of g l u c o ~ i d e s In
. ~ ~both
~
cases, however, undesirable anorners o r epimers are obtained
as by-products, which must be separated. In 1988 we developed a directed synthesis of p-mannosides which was based
on the inversion of the configuration at C-2 of glycosides
(Scheme
The P-mannosylglucosamine 3 was obtained
in an overall yield of 85 Yo via the glucosylglucosamine 2 by
intramolecular nucleophilic substitution.
Ph-NH
1. DMF, pyridine. 65%. lh
0
2.AcOH/H20/dioxane
OTf
OBZi
2
3
Scheme 1. D M F
Synthesis of a p-Mannosyl-Chitobiosyl-Asparagine
Conjugate-a Central Core Region Unit of the
N-Glycoproteins**
By Wolfgang Giinther and Horst Kunz*
N-Glycoproteins are widespread in living organisms as
membrane and serum constituents; some, e.g. the im[*] Prof. Dr. H. Kunz, DipLChem. W. Gunther
Institut fur Organische Chemie der Universitdt
Joh.-Joachim-Becher-Weg 18-20, D-6500 Mainr (FRG)
[**I This work was supported by the Deutsche Forschungsgemeinschaft and
the Fonds der Chemischen Industrie.
1050
(3
VCH kki-lag.~~e.~eIlschafi
mhH, 0.6940 Wrinheim, 1990
=
dimethylformamide. Pht
= phthaloyl
The thioglucoside 3 was now activated according to the
method described by L i i n n I 5 l using phenylselenyl triflate@],
and coupled with the glucosamine 4 (Scheme 2).
The carbonate group was removed from the p-mannosylchitobiose derivative 5, obtained in 76% yield after chromatographic purification, by treatment with sodium
methoxide/methanol, and then the N-phthaloyl protecting
groups were removed by treatment with hydrazine/ethanol.
After acetylation of the deblocked amino and hydroxy functions to give the trisaccharide 6, the benzylic protecting
groups were removed hydrogenolytically. Further acetyla-
0570-083319010909-1050 S 3.50+.25/0
Angeu. Chem. int. Ed. Engl. 29 (1990) No. 9
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