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Diastereoselective DielsЦAlder Reaction on Carbohydrate Matrices.

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which then emit from the 'Do and 'D4 levels respectively.
A contribution from charge-transfer absorption[3h1cannot
be excluded, although no such band is observed. The efficiency of conversion is high, probably about unity for
[ E d @C
The light conversion process absorption-energy transfer-emission, A-ET-E, performed by these cryptates, is represented in Figure 2.
250
300
h v'
nm
Fig. 2. Illustration of the absorption-energy transfer-emission A-ET-E light
conversion process performed by the cryptate [Eu3'c 11 (center); left: excitation spectrum (emission at 700 nm); right: emission spectrum (excitation at
320 nm); 10 - " M aqueous solution of the nitrate at 20°C; uncorrected spectra.
The emission lifetimes of the present europium cryptates
(Table 1) are longer than those of the aqua ion (0.1 1 ~ s I ~ ~ I
and even of the [Eu3@c2.2.1]cryptate (0.215
this
may be due, at least in part, to a better shielding of the
included ion by macrobicyclic ligands 1-3. Preliminary
measurements gave emission quantum yields above lo-*
for the Eu"' and Tb"'complexes of 1 and 2 (in aqueous
solution)."81 This is high for such ions, being in particular
at least an order of magnitude higher for [ E u 3 @ c11 than
for [Eu3@c2.2.1](3 x
in D 2 0 solution).13b1
Table I . Photophysical properties of europium(ii1) and terbium(iir) cryptates
of the macrobicyclic ligands 1-3 [IS] [a].
Cryptate
[Eu'"c 11
[Eu3"c 21
[Eu"C3]
[Tb'QC I ]
[ T b ' O C 21
L,Inml
Lifetime [ms]
300
3 10
280
302
310
0.34
0.41
0.27
0.33
0.72
[a] All measurements were performed in neutral aqueous solution at 300 K;
;
lifetimes f 2 0 % ; the concentrations ranged from
to 1 0 - 4 ~ lifetimes
determined at &,=619 nm for Eu"' and at ,?,,=545.5 nm for Tb"'. Anion:
NO:.
The photoactive europium(II1) and terbium(rI1) cryptates
described here are efficient luminophores which function
as A-ET-E light conversion molecular devices, transforming UV light absorbed by ligand groups into visible lanthanoid emission via intramolecular energy transfer. In addition to the interesting photophysical and photochemical
features of these and related complexes, a number of potential uses may be envisaged, for instance in the development of luminescent materials and of labels for biological
applicationsfig1
such as time-resolved luminescence immunoassays'*"] employing monoclonal antibodies.
Received: December 18, 1986;
revised: January 29, 1987 [Z 2016 IE]
German version: Angew. Chem. 00 (1987) 259
Anqew. Chem Inr Ed Engl 26 11987) No. 3
[I] JLM. Lehn, Strucl. Bonding (Berlin) 16 (1973) I ; Ace. Chem Res. I 1
(1978) 49.
[2] JLM. Lehn, Pure Appl. Chem. 52 (1980) 2303.
[3] a) N. Sabbatini, M. Ciano, S. Dellonte, A. Bonazzi, V. Balzani, Chem.
Phys. Lett. 90 (1982) 265; b) N. Sabbatini, S . Dellonte, M. Ciano, A.
Bonazzi, V. Balzani, ibid. 107 (1984) 212; c) N. Sabbatini, M. Ciano, S.
Dellonte, A. Bonazzi, F. Bolletta, V. Balzani, J. Phys. Chem. 88 (1984)
1534; d) N. Sabbatini, S. Dellonte, G. Blasse, Chem. Phys. Lett. 129
(1986) 541.
[4] G.-Y. Adachi, K. Sorita, K. Kawata, K. Tomokiyo, J. Shiokawa, J LessCommon Met. 93 ( I 983) 8 1.
[S] F. Halverson, J. S. Brinen, J. R. Leto, J. Chem. Phys. 41 (1964) 157.
[6] W. De-W. Horrocks, Jr., D. R. Sudnick, J. Am. Chem. SOC. I01 (1979)
334; Acc. Chem. Res. 14 (1981) 384.
[7] 0. A. Gansow, A. R. Kausar, K. h4. Triplet!, M. J. Weaver, E. L. Yee, J.
Am. Chem. SOC.99 (1977) 7087; E . L. Yee, 0. A. Gansow, M. J. Weaver,
rbid. 102 (1980) 2278; J. Tabib, J. T. Hupp, M. J. Weaver, Inory. Chem.
25 (1986) 1916.
[S] J.-C. G. Bunzli, D. Wessner, Coord. Chem. Reu. 60 (1984) 191.
[9] A. Heller, E. Wasserman, J. Chem. Phys. 42 (1965) 949; R. G. Charles, E.
P. Riedel, P. G. Haverlack, ibid. 44 (1966) 1356; A. Abusaleh, C. F.
Meares, Photochem. Phoiobiol. 39 (1984) 763.
[lo] J.-C. Rodriguez-Ubis, B. Alpha, D. Plancherel, J.-M. Lehn, Helu. Chim.
Acta 67 (1984) 2264.
1111 A. Caron, J. Guilhem, C. Riche, C. Pascard, B. Alpha, J.-M. Lehn, J.-C.
Rodriguez-Ubis, Helu. Chim. Acta 68 (1985) 1577.
[I21 The macrobicycle 2 has been obtained as its sodium cryptate in 35%
yield by treating the 18-membered N 2 0 4 macrocycle with 6,6'-bisbromomethylbipyridine in presence of sodium carbonate following the
method described previously for the other ligands [lo]. The same sodium
cryptate has been prepared in much lower yield by another method
[131.
[I31 E. Buhleier, W. Wehner, F. Vogtle, Chem. Ber. I l l (1978) 200.
[ 141 Anhydrous solutions of the salts were prepared by treating the commercial pentahydrates (Aldrich Chem. Co.) with a large excess (ca. 10 x ) of
trimethylorthoformate in acetonitrile under reflux for about 1-2 h. See
) also: 0. A. Gansow, K. B. Triplet!, US Pat. 4257955 (1981).
[I51 F. A. Hart, M. B. Hursthouse, K. M. A. Malik, S. Moorhouse, J . Chem.
SOC.
Chem. Commun. 1978. 549; M. Ciampolini, P. Dapporto, N. Nardi,
ibid. 1978. 788.
[I61 a) G. Anderegg, Helu. Chim. Acta 64 (1981) 1790; b) J. H. Burns, C. F.
Baes, Jr., lnorg. Chem. 20 (1981) 616; c) M.X. Almasio, F. Arnaud-Neu,
M.-J. Schwing-Weill, H d v . Chim. Aeta 66 (1983) 1296.
1171 For NMR spectra of some lanthanoid cryptates see: 0. A. Gansow, D. J.
Pruett, K. B. Triplet!, J. Am. Chem. SOC.101 (1979) 4408.
[IS] We thank N . Sabbatinr and V. Balzani (Istituto Chimico "G. Ciamician", University of Bologna) for measurements in progress on
[Eu"C 11 a s well as F. Grenier and P Bouchy (UA 328 (Prof. 1. C.
Andre) ENSIC, Nancy) for measuring the quantum yields of rhe Tb"'
cryptates.
[I91 F. S. Richardson, Chem. Reu. 82 (1982) 541.
[20] See for instance: N. J. Marshall, S. Dakubu, T. Jackson, R. P. Ekins in
A. Albertini, R. Ekins (Eds.): "Monoclonal Antibodies and Deuelopmenrs
in Immunoassay". Elsevier/North-Holland Biomedical Press, Amsterdam 1981, p. 101.
Diastereoselective Diels-Alder Reaction on
Carbohydrate Matrices**
By Horst Kunz.* Bernd Miiller, and Dirk Schanzenbach
Dedicated to Professor Helmut Hofmann on the occasion
of his 60th birthday
Numerous biochemical, immunological and molecularbiological investigations have shown that carbohydrate determinants play an important role in crucial processes of
biological
If one disregards chiral pool-syntheses, in which the carbohydrate itself is substrate, and
some chiral hydride carriers, carbohydrates have been
used only in isolated cases for the selective control of
chemical processes.I2l Stimulated by our synthesis of glycopeptides as biological recognition structure^'^^ we have
[*] Prof. Dr. H. Kunz, DipLChem. B. Muller,
D. Schanzenbach
Institut fur Organische Chemie der Universitat
J.-J.-Becher-Weg 18-20. D-6500 Mainz (FRG)
[**7 This work was supported by the Fonds der Chemischen Industrie
0 VCH Verlagsgesellschaj, mbH. 0-6940 Weinherm. 1987
0570-0833/87/0303-0267 $ 02.50/0
267
now tried to control diastereoselective reactions using the
adopts with respect to the catalyst. The arrangement in
which the oxygen atom of the furanose ring can function
“chiral information” of the carbohydrates, which may be
regarded as stereochemical microchips. We describe here
as sixth ligand for the titanium atom could be especially
the results of Diels-Alder reactionsI4’ with acrylates which
favorable. Cyclopentadiene can then attack the complex 3
are esterified with carbohydrate matrices. For diastereoseonly from the front, and obliquely from above, as shown
lective Diels-Alder reactions with amide-bound[’] or esterin Scheme 1. Hence, on preserving the endo transition state
like bound dienophiles,[61high inductions have been dethe (l’R,2’R)-S’-norbornen-2-ylcarboxylic
acid derivative 4
scribed. This holds true, in particular, for the titanium teshould be formed. The ‘H- and “C-NMR spectroscopic
trachloride-catalyzed reactions of the acrylate of (R)-pananalysis of the adduct, the separation of the diastereomers
tolactone.[’] We have now exploited the polyfunctionality
4 by flash chromatography,’81 and the reductive cleavage
and chirality of the carbohydrates in analogous Dielsof 4 to give 5-norbornen-2-ylmethanollg1confirm that the
Alder reactions in order to arrange the dienophile and the
(1 ’R,2’R)-diastereomer of the adduct 4 is indeed formed
Lewis acid catalyst on the carbohydrate matrix such that
highly selectively (93 :7). Ex0 configurated isomers could
the attack of the diene and the configuration of the main
not be detected in the product mixture. The (1 ’S,Z’S)-diaproduct can be predicted with high probability. For this
stereomer of 4 formed as by-product presumably arises
purpose the 3-O-acry~oyl-1,2-~-isopropylidene-a-~-gluco-from the Diels-Alder reaction of the syn-rotamer of 3. The
furanose 1 , which is readily accessible from 1,2,5,6-di-Oamount of syn-rotamer increases with increasing reaction
isopropylidene-a-D-glucofuranose by esterification with
temperature. Reactions of 3 with the less reactive dienes
acryloyl chloride/triethylamine and selective cleavage of
1,3-cyclohexadiene, 1,3-butadiene and anthracene lead in
the 5,6-protecting group with 70% acetic acid, is silylated
12 days at room temperature to formation of the adducts in
to give 2 in order that the titanium catalyst can be introyields of u p to ca. 30%. The diastereoselectivity drops from
duced later. 2 reacts with TiCI, at - 78°C with a change in
82 : 18 (cyclohexadiene) to 78 :22 to 70 : 30 (anthracene).
We concluded from these findings that the activity of the
titanium center should be increased in order to increase
the diastereoselectivity. We therefore prepared the
0
0
3-O-acryloyl-l,2-O-isopropylidene-5-O-trimethylsilyl-a-~\\
xylofuranose 5 from 3-O-acryloyl-l,2-O-isopropylidene-5O-trity~-a-D-xy~ofuranose
by selective acidolytic deblock(CH3),SiCI
nc1,
ing in the 5-position and subsequent silylation with trime> thylchlorosilane/pyridine. Reaction of 5 with titanium tepyridine
CH,CL,.
- 78OC
trachloride leads to formation of the complex 6 in which
the dienophile and the Lewis acid catalyst are arranged
similarly as in 3 (Scheme 2). The Lewis acidity in 6 , how2
1
ever, is increased. Cyclopentadiene reacts with 6 to give
the adduct 7 , only one diastereomer of which can be detected by chromatography and by 400-MHz ‘H- and 100MHz ”C-NMR spectroscopy.[“” The reduction of 7 to S norbornen-2-yl-methanol confirmed that 7 was the expected (1 ’R,2’R)-diastereomer.
3
4
Scheme I.
color to give 3; trimethylchlorosilane is formed as a volatile, readily separable by-product. Completion of the exchange can be controlled by thin-layer chromatography.
However, because of the instability of the chlorotitanate 3,
its isolation and exact characterization is not possible. The
direct reaction of diols such as 1 or their anions with
TiCl,, on the other hand, yields HCI- or salt-containing
chlorotitanates whose catalytic activity is strongly reduced.
In the acrylates 1-3, the a$-unsaturated carbonyl system
is apparently present in the anti conformation, since the
signals of the vinyl protons appear in the sequence
(61,.z > 6, > i&characteristic
)
for normal acrylates. This is
consistent with the observations made on lactate enoates,
in which the Lewis acid catalyst, as here, attacks exclusively at the carbonyl oxygen atom of the enoate.[61In the
reactive complex 3, the dienophile and the titanium catalyst are so fixed that the Re side of the dienophile is
shielded, irrespective of which conformation the side chain
268
5 VCH Vertagsgesetfscliafi mbH. 0.6940 Wemheim, 1987
5
C
A
- 78%
HoQ$
O b
7
73%, ( R ) : ( S )
>
98 : 2
Scheme 2.
0570-0833/87/#303-#268
S #2.50/0
Angew. Chem. lnl. Ed. Engl. 26 (1987) No. 3
These results show that the chiral information of carbohydrates can be used for directed stereoselective control by
binding reversibly several reaction components in a definite way to the functional groups of the carbohydrate matrix.
Received: October 31, 1986;
supplemented: December 5 , 1986 [Z 1975 IE]
German version: Angew. Chem. 99 (1987) 269
[ I ] Short review, e.g. N. Sharon, Trends Biochem. Sci. Pers. Ed. 9 (1984)
198.
[2] a) S. Brdndange, S. Josephson, L. Morch, S. Vallen, Acta Chem. Scand.
Ser. 8 3 8 (1981) 273: b) C. H. Heathcock, C. T. White, J. J. Morrison, D.
Van Ilerveer, J. Org. Chem. 46 (1981) 1296; c) 1. Hoppe, U. Schollkopf,
R. Tolie. Synthesis 1983. 789; d) S . Danishefsky, J. Aube, M. Bednarski,
J . A m . C k m . Sac. 108 (1986) 4145.
[3] Review: H. Kunz, Angew. Chem.. in press.
141 Review on the asymmetric Diels-Alder reaction: W. Oppolzer, Angew.
Chem 96 (1984) 840; Angew. Chem. Int. Ed. Engl. 23 (1984) 876.
[ 5 ] a) D. A. Evans, K.T. Chapman, J. Bisalia, J. A m . Chem. SOC.I06 (1984)
4261; b) W. Oppolzer, C. Chapuis, G. Bernardinelli, Helc. Chim. Acto 67
(1984) 1397.
[6] Recent review: G. Helmchen, R. Karge, J. Weetman: Modern Synthetic
Methods. Vol. 4. Springer, Berlin 1986, p. 261 ff.
171 T. Poll, A. Sobczak, H. Hartmann, G. Helmchen, Tetrahedron Leu. 26
(1985) 3095.
[8] (I’R,2’R)-4: ‘H-NMR (CDCI;): 6=5.85 (d, J(1,2)=3.7 Hz; H-I), 2.98
(dt, J(2’,3‘endo)=J(2’,1’)=3.9 Hz, J(2’,3’exo)=9.3 Hz; H-2’); ”CNMR: 6= 174.8 (C=O), 138.0 (C-57, 104.8 (C-I), 83.2 (C-2): R,=0.40
(petroleum ether 40-70/acetone l / l ) . [a]?= f89.5 (c= I g/IOO mL,
CHCI,). (I’S,2’S)-4: ‘H-NMR (CDCI;): 6=5.88 (d, J(1.2)=3.7 Hz; HI), 3.02 (ddd, J(2’,3’endo)=3.85 Hz, J(2’,1’)=4.0 Hz, J(2’,3‘exo)=9.3
Hz: H-2’); ”C-NMR: 6 = 175.0 (C=O), 138.4 (C-5’), 104.9 (C-I), 83.0
(C-2); R r = 0.37 (petroleum ether/acetone l / l ) . The product still contains ca. 10% of the (I’R,2’R) diastereomer.
191 [a]::=+65.9 (c= I , ethanol), obtained from the diastereomeric mixture
4 ; (2S)-endo-5-norbornen-2-yl-methanol:
[alD=- 76.6 (95% ethanol) according to J. A. Berson, J. Singh Walia, A. Remanick, S. Suzuki, D. Reynolds-Warnhoff, D. Willner, J. Am. Chem. Soc. 83 (1961) 3986; (2R)endo-5-norbornen-2-yI-methanol:
[a]L2=+76.1 (c=0.9, EtOH) see E. J.
Corey, H. E. Ensley, ibid. 97 (1975) 6908.
[ l o ] (I’R,2’R)-7: ‘H-NMR (CDCI,): 6=5.89 (d, J(1,2)=3.6 Hz; H-I), 2.95
( m ; H-2‘). ”C-NMR: 6= 174.5 (C=O), 138.2 (C-5’). 104.6 (C-I), 83.7 (C2); [ a ] g =+84.2 (c=0.33, CHCI,).
BOOK R E V I E W S
Chemistry of Hydrocarbon Combustion. By D. J. Hucknall.
Chapman & Hall, London, New York 1985. viii, 415 pp.,
bound, .€ 39.50.--ISBN 0-412-26110-3
The problems and methods of investigation in the chemistry of hydrocarbon combustion are of an analytical nature. The questions posed are: What types of reactions and
intermediates are involved in the combustion? What are
the rates of the individual steps in the reaction? How are
these steps interconnected with regard to the transfer of
matter and energy? The book reviewed here is aimed at
obtaining answers to these questions. The treatment of the
problem can be divided roughly into three sections:
1. Determining the possible reaction products that can re-
sult from oxidation o r thermal decomposition under
various conditions of combustion (Chapters 1, 2 and
part of Chapter 6).
2. A description of the tools used by the combustion
chemist, divided into “hardware” (apparatus and investigational techniques), and “software” (information o n
reaction mechanisms and rate constants).
3. Computer-aided studies which are aimed at simulating
and understanding the entire combustion process and
the macroscopic observations, starting from reaction
mechanisms and kinetic data.
The first group of topics is treated mainly from a historical standpoint. Results obtained for different fuels are followed by a description of theories of hydrocarbon oxidation proposed during the 1920’s and 1930’s. Similarities of
the combustion of various hydrocarbons (induction times,
auto-catalytic behavior, negative temperature coefficients,
etc.) are outlined, and important stages in the theoretical
interpretation (hydroxyl chemistry, branching of reaction
chains according to Semenow. peroxide theory, etc.) are
explained. The development of more sensitive analytical
techniques (mass spectrometry, gas chromatography) on
the one hand, and the introduction of methods for transient measurements on the other, are reflected in the
greater wealth of analytical data and the increasingly deAngew. Chem. Int. Ed. Engl. 26 (1987) No. 3
tailed reaction mechanisms arising in the 1960’s and 1970’s
(Chapter 2). By this historically oriented treatment, the
author puts u p with the fact that without a knowledge of
the important reaction mechanisms discussed later, the
analytical results from early studies and the interpretations
based on them appear confusing and lacking an unbroken
thread.
Chapters 3 to 5 comprise an excellent review of modern
techniques for investigating the basic reactions of combustion processes and measuring their kinetic parameters.
This is a critical presentation which also examines theoretical aspects of the interpretation of rate constants and
their dependence o n temperature and pressure. One chapter is devoted to free radical reactions of the hydrogenoxygen system and another to those of carbon-containing
compounds. It becomes clear how closely related the combustion chemistry of hydrocarbons is to the hydrogen-oxygen system. I enjoyed these chapters the most.
There follows a chapter on the pyrolysis of hydrocarbons, insofar as this is important in relation to combustion
reactions, half of this being devoted to soot formation in
flames. Here one is a little disappointed at not finding an
account of the progress made recently using laser optics
methods. Also the fact that soot formation is treated in the
chapter on pyrolysis obscures to some extent the important
role that oxidation reactions also have in this process.
The book concludes with a briefer survey of methods
and progress in modelling complex combustion systems
(flames, pyrolyses and oxidations at intermediate temperatures).
Taken as a whole the book mainly has the character of a
review. Its strength lies in its concise presentation, limited
to the basic essentials, of results from important investigations covering seven decades of combustion research. This
is supported by the extremely comprehensive bibliography, containing about 2200 references. Regrettably,
though, the author has not quite succeeded in clearly correlating the results of different investigators, nor in reducing complex combustion reactions to their essential features and thereby making them comprehensible to chem269
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