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Graphical Abstract (Angew. Chem. Int. Ed. Engl. 211995)

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A z u r n a l of the
- -~
International Edition in English
Pages 2299 - 2426
The cover picture shows not skydivers, but molecules of trimethylisocyanurate linked
with CH . . ' 0 hydrogen bonds in the layered hexagonal crystal structure of the 1 : 1
complex formed by this substance with 1.3,5-trinitrobenzene. But supramolecular
patterns in crystals resemble the aerial patterns formed by skydivers in that properties of'the group are distinct from those of the individual constituents. In this sense,
a crystal of an organic compound is the perfect supermolecule and crystal engineering, which is the deliberate design of crystal structures of organic compounds, is the
supramolecular equivalent of organic synthesis. By defining a "supramolecular synthon" as a building block that incorporates both chemical and geometrical features
of sets of intermolecular interactions, the conceptual similarity between crystal engineering and classical organic synthesis is uncovered. This striking parallel is discussed by G. R. Desiraju on pp. 2328.
The synthesis of structurally and functionally complex supramolecular compounds
from simple building blocks is a particular challenge. Template-controlled, multistep
processes in homogeneous solution (see Scheme) are of great use for this synthesis.
The chemistry of. for example, intercalation compounds, silicates with framework
structures like zeolites, or polyoxometalates offers ample illustrative material for a
blossoming branch of inorganic chemistry.
A. Miiller.* H. Reuter,*
S. Dillinger ...___.__....._..._.________
231 1 -2327
Small Guests in Small and Large Hosts
The retrosynthetic analysis of a crystal structure is the first step towards the design
of solid-state targets. The procedure provides supramolecular synthons (for instance, -NO,. .. I-, see scheme below), which should be understood as spatial
arrangements of intermolecular interactions. This type of synthon plays the same
focusing role in the synthesis of solids as the conventional synthon in classical
organic synthesis. Therefore, supramolecular synthons are accessible structural
units that can be linked to form the target supermolecule.
G. R. Desiraju* .....................
Supramolecular Synthons in Crystal Engineering-. A New Organic Synthesis
Amide 1 is not the universal sleep-inducing substance, and no appropriate receptors
have been found in the brain, but naturally occurring 1 does induce sleep. Compound 1 was found in the cerebrospinal fluid of sleep-deprived animals. Recent
research on this compound and others with similar effects have led to a better
understanding of the phenomenon of sleep. at least on a molecular level.
T. Kolter, K. Sandhoff* ......... 2362-2364
New Brain Lipids that Induce Sleep
" 2H
An alternative to matrix isolation, cold molecules can be trapped and aligned in
vacuum by an intense infrared laser field according to theoretical considerations
expounded recently. The method is based on the polarization of the molecules by the
electric field of the light, which creates an attractive potential. If the polarizability
of the molecules is anisotropic, the axis of highest polarizability will be aligned along
the polarization direction of the laser.
L. Kador* .............................
Aligning and Trapping Molecules with
H. Hopf,* P. G. Jones, P. Bubenitschek,
C. Werner ..............................
The highly reactive intermediates 1 and 2 with cumulative double bonds in para and ortho positions, respectively, react to give products with isolated triple
bonds. Intermolecular dimerization of 1 yields a
paracyclophanetetrayne, which assumes two conformations in the crystal. Compound 2 reacts by
intramolecular cyclization affording a highly
strained cycloocta-3-ene-l15-diyne derivative.
para- and ortho-Quinodimethanes Intermediates with Cumulative Double Bonds
Lithium phenyl phosphanide and acetonitrile react readily to give the lithium complex
1. The compound crystallizes as a dimer and can be converted by protonation into
the thermally stable phosphaalkene 2. This in turn could be suitable for the synthesis
of heteropolyenes.
A Simple Route to the I-Aza-3-Phosphaally1 System: Structure of a Dimeric Lithium ComDlex and Protonation To Give the
First NH,-Substituted Phosphaalkene
K. Paasch, M. Nieger,
E. Niecke* .............................
~c)VCH ~ ~ r . l u g s ~ e s e l l . ~mc /hi uHf,~0-69451 Weidic,ini, I 9 9 5
0570-0N33/95/3421-2302 S tO.OU+ ,2510
Angew. Chem.
In[. E d Engl. 1995. 34, N o . 2 t
Stabilized by "carbene" donor ligands, the Pd complex 1 catalyzes the Heck olefination of aryl halides
unexpectedly efficiently and yet has long-term stability at elevated temperatures. The active Pdo species can be generated during the Heck reaction or
deliberately prepared by reduction of 1 with, for
instance, hydrazine or sodium formate. Another
similar catalyst can be synthesized in situ from Pdo
complexes and I .3-dimethyldi hydroimidazoline-2ylidene.
W. A. Herrmann,* M. Elison. J. Fischer,
C. Kocher, G . R. J. Artus ...... 2371 - 2374
Metal Complexes of N-Heterocyclic
Carbenes- A New Structural Principle for
Catalysts in Homogeneous Catalysis
A distorted cubic lattice of 1; ions, in whose cavities
the complex cations [Ag([18]aneSJi ([18]aneS, =
are encapsulated, is formed in the synthesis of 1 (section of
structure shown on the right). I ions are positioned
at the lattice points; one I2 molecule is located along
each edge. The Ag' ions function as a secondsphere template in the synthesis of the 1; polyanion.
A. J. Blake, R. 0. Gould, S. Parsons,
C. Radek, M . Schroder* _ . . . . _ ,2374-2376
The breakdown of the polymeric structure of alkali metal cyclopentadienides can be
achieved by (Me,N),S'Cp[(TAS)Cp]. This leads to the salts TAS'[Cp,M]( M = Li. N a , Kj. On the other hand, [TAS,Cp]+[Cp,M]- salts are obtained if this
reaction is carried out in the molar ratio 2: 1 ; the structure analysis of the Na
compound shows that sandwich and inverse sandwich units are present side by side.
J. Wessel, E. Lork.
R. Mews* ...............................
Self-Assembly of Polyanions at a Metal
Cation Template: Syntheses and
Structures of [{Ag([18]aneS,,)j I7In
and [Ag([l8]aneS6)]T,
Alkali Metallocene Anions: Syntheses and
A kinetic template effect directs selection in
competitive self-assembly of tetracationic
cyclophanes (represented by a circle) containing 177c1u- or par-dinked 4,4'-bipyridinium and/or bis(4-pyridinium)ethylene units
in the presence of competing crown ether
templates (represented by a square or a triangle). The cyclophane fragments first couple covalently to form an intermediate
(represented by an arc). and then the molecular recognition event strings the crown
ether before the rate-determining second covalent bond formation closes the ring.
D. B. Amabilino. P. R. Ashton,
L. Ptrez-Garcia,
J. E Stoddart* .......................
Two interlocking substructures~-infinitechains of 8-cyclodextrin monomers and
[Mg(H,O),]CI2 building blocks-form the basis o f a novel composite. The chains of
inorganic components. comprising Mg(H,O), octahedra linked through C1 anions
and water of'crystallization, are threaded through the cavities of the cyclodextrins.
The complete structure is stabilized by hydrogen bonds.
I. Nicolis, A. W. Coleman. P. Charpin,
C. de Rango* ........................
2381 -2383
Yes indeed. radical additions to arene-Cr(CO), complexes are possible. Treatment
of the chiral complex 1 with SmI, gives tricycle 2 selectively by a 5-endu-trig radical
cyclization: dihydro-1 is converted into the demethoxylated complex 3. In the latter
case the ketyl radical adds directly to the complexed arene.
\ OMe
\ OMe
\ OMe
Kinetic Selection in the Template-Directed
Self-Assembly of [2]Catenanes
A Molecular Composite Containing Organic and Inorganic Components- A
Complex from P-Cyclodextrin and Hydrated Magnesium Chloride
H.-G. Schmalz,* S. Siegel,
J. W. Bats ..............................
Radical Additions to (if'-Arenej(tricarbony1)chromium Complexes: Diastereoselective Synthesis of Hydrophenalene
and Hydrobenzindene Dcrivatives by Samariurn(I1) Iodide Induced Cyclization
Simply inverting the orientation of the amide function
as in 1 compared to that of the ligand series derived
from 2-diphenylphosphinobenzoic acid affects the
enantiomeric discriminating step in the Pd-cataPh2P
lyzed nucleophilic alkylation of meso-I ,4-dihy0 ' ; o
droxy-2-cycloalkenes. In reactions such as this, the
bond-making or -breaking event occurs outside the
coordination sphere of the metal. The chiral scaffold of the ligand is connected to
the metal atom by a linker (here 2-diphenylphosphinoaniline), and the preferred
conformation of the catalysts provides "chiral spaces" for the substrate- -a conclusion supported by X-ray crystallography.
Unexpected eliminations defeated
attempts to synthesize alkylcobaloximes substituted with a- and 8heteroatoms. However. synthesis of
the y-substituted alkylcobaloxime 1,
a functionalized coenzyme B, model, was successful in only a few steps.
The key step was an acyloin condensation for the preparation of the
dioxime ligand.
s y s l R 3
A New Platform for Designing Ligands for
Asymmetric Induction in Allylic Alkylations
B. Kohler, M. Knauer, W. Clegg,
M. R. J. Elsegood, B. T. Gelding,*
J. Retey* ..................................
Peripherally Substituted Cobaloximes;
X-Ray Crystal Structure Analysis of crHexylbis[l,8-di(N-morpholino)octane-4,5dioximatoJpyridinecobalt(~~~)
Irrespective of the geometry of the double bond the configuration of the newly formed
chiral center is established by the existing adjacent stereogenic center in the Lewis
acid catalyzed cyclization of the N-acyliminium silyl enol ether intermediate 1. This
step is the key transformation in a new, concise total synthesis Of D-( +)-biotin. R =
protecting group.
B. M. Trost,* B. Breit, S. Peukert,
J. Zambrano. J. W. Ziller .....__.2386-2388
M. J. Moolenaar, W. N. Speckamp,*
H. Hiemstrd, E. Poetsch,
M. Casutt ..............................
2391 -2393
Synthesis of D-( +)-Biotin through Selective
Ring Closure of N-Acyliminium Silyl Enol
H " y ~ ~ 2 ) 4 ~ ~ 2 ~
L. Banfi, G. G u m t i * ........._...2393-2395
A promising prodrug, the stable cyclic enediyne 1,
unleashes a reactive, potentially DNA-damaging
enediyne when the 8-lactam group is hydrolyzed
under basic conditions. This intermediate rapidly
undergoes cycloaromatization giving a phenylene
diradical, which can be trapped by 1,4-cyclohexadiene. R', R Z = OMe, H.
Lactendiynes: A New Class of Triggered
Cyclic Enediynes
The Lewis acid mediated transfer of an alkoxide ligand from the chiral ligand sphere
of 1 facilitates the highly enantioselective ring-opening of cyclic C,-symmetric anhydrides 2 to the corresponding hemiesters 3 with enantiomer ratios up to 99: 1. This
ability to transfer ligands could make 1 an organometallic alternative to hydrolytic
enzymes, as the differentiation of enantiotopic functional groups in meso compounds and the resolution of racemic substrates should be possible.
D. Seebach,* G. Jaeschke,
Y M. Wang ............................
Highly Enantioselective Opening of Cyclic
rneso-Anhydrides to Isopropyl Hemiesters
with Diisopropoxytitanium TADDOLates
t> VCH Verlugspsrllschufr mhH, 0-69451 Weinheim, 1995
057f1-0833/95/3421-2304$ 10.00+ .25/0
A n g m . Chem. hi.Ed. Engl. 1995. 34, N o . 21
An angucycline antibiotic with a nonaromatic Bring, (+)-SF2315A (3), was synthesized enantioselectively for the first time. A key transformation in the 23-step reaction sequence. which starts from (-)-quinic acid, is the stereocontrolled Diels-Alder
reaction between diene 1 and bromojuglone 2. TIPS = triisopropylsilyl.
K . Kim, G . A. Sulikowski* _ _ .2396-2398
Total Synthesis of Natural (+)-SF2315A
and Determination of the Absolute Configuration
0 O m C H ,
TI P S O , . , , , ~ ~3
SF2315A 3
Enzyme kinetics and EPR spectroscopy provide evidence that in the reversible rearrangement of (S)-glutamate (1) to (2S,3S)-3-methylaspartate (2), which is catalyzed
by the coenzyme B,, dependent glutamate mutase from Clostridium cocklearium, the
substrate 1 fragments into acrylate (3) and glycine radical (4), which recombine to
2. Ado-CH,-Cbl = 5'-adenosylcobalamin (coenzyme B, ,).
Both aromatic and aliphatic Schiff bases 1 can be cyclized asymmetrically in the
presence of titanium alkoxides if N.N-phthaloyl-protected amino acids are employed as chiral auxiliaries. The desired heterocycles 3, which are suitable for alkaloid syntheses, are formed with diastereomer ratios of up to 99%. R = nPr, iPr;
R ' = Me, Et. iPr. Ph, Ar; R2 = Me, iPr, tBu.
From the temperature-dependent HPLC retention of
a guest or host on a chemically bonded stationary
phase containing the complementary component (as
shown schematically on the right), the complexation
enthalpies of a series of hydrogen-bonded hostguest complexes can be rapidly and conveniently
determined. The AH' values determined in this way
agree within experimental error with the complexation enthalpies measured in free solution by traditional methods.
j-Silylethoxy-protected phosphoramidites are useful
reagents for the synthesis of O,O,O-trialkylphosphorothioates of type 1 in solution, which are interesting as building blocks for antisense oligonucleotides. Trialkylsilyl substituents in the @-positionpromote rapid thiono-- thiolo rearrangement through
neighboring group participation (8-silicon effect).
Selective deprotection under mild conditions
through /&fragmentation yields only O,O-dialkylphosphorothioates. T = N'-thyminyl.
B. Beatrix, 0. Zelder, F. K. Kroll.
G. Orlygsson, B. T. Gelding,*
W. Buckel* ......................... ... 2398-2401
Evidence for a Mechanism Involving
Transient Fragmentation in Carbon
Skeleton Rearrangements Dependent on
Coenzyme B,
H. Waldmann,* G. Schmidt, H. Henke,
M. Burkard ...........................
Asymmetric Pictet-Spengler Reactions
Employing N,N-Phthaloyl Amino Acids as
Chiral Auxiliary Groups
______ H-N?c
S. C. Zimmerman,*
W.-S. Kwan ............................
A Comparison of Enthalpies of Formation
in Solution and Enthalpies for HPLC Re-
A. H. Krotz,* P. Wheeler,
V. T. Ravikumar ..................._2406-2409
Phosphorothioates: \]-Fragmentation versus 8-Silicon Effect
, T
Electron transfer between two heme proteins can be readily observed if one of the
proteins is immobilized on an electrode. The signal transduction following the
molecular recognition occurs at the phase interface, as it does in nature, and can be
directly monitored by cyclic voltammetry. The picture shows schematically the
course of the reaction for the examDle of immobilized cvtochromec.
Nucleophilic attack of the bridging 0x0 ligand is the
key step in the hydrolysis of the bridging phosphate
diester in complex 1. This hydrolysis is lo1' times
faster than the hydrolysis of the free phosphate diester. Thus, the phosphate-free C o complex is an
interesting model of enzymes having two metal
atoms in the active site.
L. Jiang, C. J. McNeil,
J. M. Cooper* ........................
Direct Electrochemical Coupling of ComDonents of the Biological Electron Transfer
Chain to Modified- Surfaces: Molecular
Recognition between Cytochrome c Peroxidase and Cytochrome c
D. Wahnon, A.-M. Lebuis,
J. Chin* .................................
Hydrolysis of a Phosphate Diester Doubly
Coordinated to a Dinuclear Cobalt(m)
Complex: A Novel Mechanism
S. E. Dann, P. J. Mead,
M. T. Weller* .........................
Ca,[Ga,SiO,j,(OH), is the first gallosilicate containing Ga-0-Ga links. The gallium-rich compound
crystallizes in a sodalite structure, in which the number of Ga-0-Ga links is minimized, according to
Lowenstein's rule, by surrounding each SiO, tetrahedron by four GaO, tetrahedra. The hydroxide
ions present in the sodalite cage are disordered and
form weak hydrogen bonds with the framework
oxygen atoms (depicted on the right).
A Framework Containing Ga-0-Ga Links:
The Synthesis and Structure of Gallobicchulite Ca,(Ca,SiO,),(OH),
The first aqua complex of an element of group 15,
namely the [Bi(HzO),]3' ion (shown on the right) in
bismuth(nr) trifluoromethanesulfonate enneahydrate, has been detected. Hence the last gap in the
systematics of aqua complexes of main group metals
has been closed. The central Bi3+ ion in the C3,,symmetric coordination polyhedron-a
trigonal prism-shows no recognizable stereochemical activity of the lone pair of electrons in the solid
W. Frank,* G. J. Reiss,
J. Schneider ............................
The Nonaaquabismuth(ir1) Cation
* Author
to whom correspondence should be addressed
BOOKSNucleophilic Aromatic Substitution of Hydrogen
V. N . Charushin, H. C. van der Plas
. 0. N. Chupakhin,
The Jewish Alchemists. A History and Source Book
Keyword Index 2422
R . Patai
Author Index 2423
M . Mgkosza ....................................
G. B. Kaufjman ................................
Preview 2424
The following reviews will appear in future issues:
Palladium-Catalyzed Synthetic Reactions of Propargylic Compounds
J. Tsuji, T. Mandai
Computer-Assisted Planning of Organic Chemical Synthesis: The Second Generation
J. Gasteiger and W.-D. Ihlenfeldt
Organic Synthesis on Solid Supports
G. Jung. J. B. Friichtel
Electronegativity and Molecular Properties
J. Hinze and D. Bergmann
Copper -A ”Modern” Bioelement
W. Kaim. J. Rall
The Schenck Ene Reaction : Diastereoselective Oxyfunctionalization with Singlet Oxygen in Synthetic Applications
W. Adam, M. Prein
MetallophosphaalkenesFrom Exotics to Versatile Building Blocks in Preparative Chemistry
L. Weber
Electroii Domains and the VSEPR Model of Molecular Geometry
R. J. Gillespie and E. A. Robinson
Protonation of Unsaturated Hydrocarbon Ligands: Regiospecificity, Stereospecificity, and Product Specificity
R. A. Henderson
Stereocontrol in Organic Synthesis Using the Diphenylphosphinoyl (Ph,PO) Group
J. Clayden and S. Warren
Photobiological Switches
I . Willner
Nonstabilized Alkyl Complexes and Alkyl-Cyano-Ate Complexes of Iron(n) and Cobalt(I1) as New Reagents in Organic Synthesis
T. Kauffmann
Al(r) and G;I(I) Compounds: Preparation, Structures, and Reactions
H. Schniickel
Chemistry-A European Journal may be found after page
2424 with its own table of contents and separate pagination.
I N / .Ed. Enxl 1995, 34, N o . 21
mhH, 0-69451 Wemheim, 1995
o57U-O#33!95:3421-2307 Y 10.00
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