© WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Volume 42, Issue 34
Rupali R. Davda and James A. Dumesic
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200390562
CO-poor hydrogen can be produced by reforming oxygenates, such as ethylene glycol, in water over Pt catalysts. The expansion of the gas bubbles formed in the process by the vaporization of water results in a decrease in the partial pressures of H2 and CO2, thereby favoring the water–gas shift and lowering the CO concentration. This process leads to the production of fuel-cell-grade H2 at high pressures. For more information see the Communication by J. A. Dumesic and R. R. Davda on page 4068 ff.
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200390563
Vivian Wing-Wah Yam, Xiao-Xia Lu and Chi-Chiu Ko
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200390564
Takashi Ooi, Takashi Miki, Mika Taniguchi, Misato Shiraishi, Mifune Takeuchi and Keiji Maruoka
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200390567
K. C. Nicolaou, Tamsyn Montagnon and Phil S. Baran
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200390568
Pierre-Yves Renard, Philippe Vayron, Eric Leclerc, Alain Valleix and Charles Mioskowski
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200390569
Holger Sültmann and Reiner Dahint
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200390565
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200385999
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200385994
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200301667
Straightforward access to helicene-like molecules (see structure) is possible by short and efficient protocols that have emerged in the past few years. These transformations, as well as recent approaches to chiral nonracemic derivatives, constitute a significant advancement in synthetic methodology.
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200330059
He counts as one of the co-founders of physical chemistry, contributor to scientific research and organization, scientific publicist, and color researcher. This year marks the 150th anniversary of the birth of Wilhelm Ostwald, Nobel Prize winner in 1909.
Lutz F. Tietze, Hubertus P. Bell and Srivari Chandrasekhar
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200200553
Unlimited options: The synthesis of natural product hybrids by combining structurally different, naturally occurring compounds that exhibit high biological activities appears to be a promising approach to increase the number and diversity of substances for pharmacological testing. An example is the hybrid of estrone and (−)-talaromycin (see picture).
Florian Kraus, Jürgen C. Aschenbrenner and Nikolaus Korber
Version of Record online: 14 AUG 2003 | DOI: 10.1002/anie.200351776
Aromatic P: Among the homoatomic polyanions of group 15 elements, Bi42− and Sb42− have been exotic curiosities for a long time, as they are potential 6π aromatic rings. As42− joined as the lighter congener as recently as 2002. Considering the diagonal relationship of P to C, the cyclobutadienediide analogue P42− would be expected naturally, but only now has it been prepared in the form of Cs2P4⋅2 NH3 from diphosphane(4).
Peter Langer and Gopal Bose
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200351263
Domino reactions of 1,3-bis(silyl enol ether)s with 1,1-diacetylcyclopentane and 1,1-diacetylcyclopropane (see scheme) allow a new and convenient one-pot synthesis of spiro[5.4]cyclodecenones, bicyclo[4.4.0]deca-1,4-dien-3-ones, and functionalized salicylates, which are versatile intermediates for the synthesis of pharmacologically relevant natural product analogues. MS=molecular sieves.
Reinhart Ahlrichs, Christopher E. Anson, Dieter Fenske, Oliver Hampe, Alexander Rothenberger and Marek Sierka
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200351395
A prismatic prison for chloride: Partial disproportionation of CuCl during the reaction with KOtBu leads to the formation of a mixed-valence CuI/CuII alkoxido complex. The trigonal prismatic K6(μ6-Cl) template in the middle of the complex is capped by two [CuII(OtBu)3]− and three [CuI(OtBu)3]− units (see picture, Cl green, Cu light blue, K yellow, O red).
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200351648
Back to bases: What happens, if three nitrogen lone pairs are forced to interact with each other? An extraordinary increase in basicity. This conclusion is the result of DFT calculations which, for example, predict a pKa value (of the conjugate acid, in acetonitrile) of 30.2 for tris(8-quinolyl)borane 1. The basicity is due to a strongly destabilizing interaction between the three quinoline lone pairs in the free bases.
Fabrice Denes, Fabrice Chemla and Jean F. Normant
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200250474
Radical processes explain the reactivity and selectivity observed in a one-pot, two- or three-component domino reaction, which consists of 1,4-addition, carbocyclization, and quenching with electrophiles. This radical–polar crossover reaction leads stereoselectively to 3,4-disubstituted 3-methoxycarbonylpyrrolidines (see scheme).
Yit-Yian Lua, Michael V. Lee, William J. J. Fillmore, Reija Matheson, Amarchard Sathyapalan, Matthew C. Asplund, Steven A. Fleming and Matthew R. Linford
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200250846
The reaction of epoxides with a bare silicon surface is reported (see scheme). Diepoxides yield amine-reactive monolayers on scribed silicon. Controlled levels of epoxide functionality are obtained in mixed monolayers of 1,2-epoxyoctane and 1,2,7,8-diepoxyoctane.
Pelayo Camps, José A. Fernández, Santiago Vázquez, Mercè Font-Bardia and Xavier Solans
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200351070
Simultaneous formation of four CC bonds and three rings occurs in the unique uncatalyzed thermal [2+2+2+2] cycloaddition to give the tridecacyclotetracosane derivative 2, which takes place when the highly pyramidalized alkene 1 is generated in the absence of a trapping agent (see scheme).
James McNulty, Alfredo Capretta, Vladimir Laritchev, Jeff Dyck and Al J. Robertson
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200351209
Intimate details of the Mitsunobu mechanism: The trapping of an acyloxytributylphosphonium ion with a chiral secondary alcohol leads to either retention or inversion of stereochemistry in the resulting ester depending on the exclusion or inclusion of a base (see scheme). Insight into the mechanism of phosphorane-mediated esterification processes is presented.
Guanyang Lin, Nathan D. Jones, Robert A. Gossage, Robert McDonald and Ronald G. Cavell
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200351320
Carbon monoxide replaces cod in the mono carbene phosphane imine complex 1 (see picture) to form, through a double silyl migration reaction, the remarkable complex 2 containing three carbene centers bound to platinum (cod=cycloocta-1,5-diene).
Atsushi Shimojima and Kazuyuki Kuroda
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200351419
Lamellar and hexagonal structures of new silica-based hybrids were directly formed from newly designed alkylsiloxane oligomers 1. This approach based on the self-assembly of single precursors provides a novel pathway to ordered microporous silica as well as mesostructured silica-based hybrid materials (see scheme, 1) hydrolysis and polycondensation, 2) self-assembly).
Myung-Seok Choi, Takuzo Aida, Hongxia Luo, Yasuyuki Araki and Osamu Ito
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200351460
Energy funnels: A large dendritic zinc porphyrin heptamer (7PZn) in a C60-terminated electron-transfer relay system 7PZn-C60 (see picture) not only harvests visible light for the electron transfer to the C60 terminus, but also retards the back-electron-transfer process, thus resulting in a longer lifetime of the charge-separated state (7P-C).
Wai-Yeung Wong, Li Liu and Jian-Xin Shi
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200351672
The light fantastic: The first examples of soluble high-molecular-weight d10 mercury(II) polyyne copolymers incorporating a 9,9-dialkylfluorene moiety have been prepared and photophysically characterized (see picture). These polymers have been shown to utilize a heavy-atom effect in exhibiting strong phosphorescence.
Version of Record online: 18 JUN 2003 | DOI: 10.1002/anie.200351664
Vaporization of water leads to low levels of CO: Now, it is possible to produce low-CO-containing, H2-rich streams by simple, aqueous-phase reforming of oxygenates. The schematic of ethylene glycol reforming on a Pt catalyst shows the composition of a gas bubble in the aqueous-phase reactor. Lowering the H2 and CO2 pressures, by increasing the water pressure, lowers the CO concentration in the product. WGS= water–gas shift.
Anne F. Richards, Håkon Hope and Philip P. Power
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200351907
The first, well-characterized, polyhedral cluster with two different heavier group 14 elements is prepared (see picture). Low-valent group 14 halides are used to synthesize species in which the majority of the group 14 atoms carry no organic substituents.
Hye-Young Jang, Ryan R. Huddleston and Michael J. Krische
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200351986
Since the discovery of catalytic homogeneous hydrogenation in 1938, CC bond formation has only been observed under hydrogenation conditions in alkene hydroformylation and Fischer–Tropsch-type processes, that is, in catalytic processes involving migratory insertion of carbon monoxide. As revealed in the present study, organometallic intermediates obtained upon diene hydrogenation are subject to electrophilic trapping by glyoxal partners, thus demonstrating catalytic CC bond formation under hydrogenation conditions in the absence of carbon monoxide (see scheme). DCE: 1,2-dichloroethane. R=aryl, heteroaryl, alkyl.
K. C. Nicolaou, Casey J. N. Mathison and Tamsyn Montagnon
Version of Record online: 8 AUG 2003 | DOI: 10.1002/anie.200352076
New reactions for the synthetic toolbox: 2-Iodoxybenzoic acid (IBX) was employed to access a diverse array of useful synthetic intermediates. Among other transformations, the developed chemistry converts amines into imines, dithianes into carbonyl groups, N-heterocycles into N-heteroaromatic compounds, and hydroxylamines into oximes in high yields.
Ryo Shintani and Gregory C. Fu
Version of Record online: 8 AUG 2003 | DOI: 10.1002/anie.200352103
A planar-chiral Cu/phosphaferrocene–oxazoline catalyst mediates intramolecular Kinugasa reactions to give tricyclic β-lactams with good enantioselectivity. A variant of the process, in which a postulated enolate intermediate is intercepted with an electrophile in a transformation that generates two CC bonds, a CN bond, two new rings, a carbonyl group, and adjacent tertiary and quaternary stereocenters (see scheme), supports the proposed mechanism.
Cheng-Yong Su, Mark D. Smith and Hans-Conrad zur Loye
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200351353
Self-cyclization of four HgCl2 units and four ditopic 1,3-bis(benzimidazol-1-ylmethyl)-2,4,6-trimethylbenzene (bbimms) ligands has resulted in the assembly of the neutral nanotube [Hg4Cl8(bbimms)4] containing two compartments which can accomodate DMF and DMSO guest molecules (see picture). Crystal packing arranges all the tubes into an extended pipeline structure.
Yu Wang, Jihong Yu, Min Guo and Ruren Xu
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200351643
A twist in the tale: A racemic mixture of the chiral [Co(dien)2]Cl3 complex has been used as a template in preparing an open-framework zinc phosphate with multidirectional helical channels, consisting of alternate ZnO4 and PO4 tetrahedra. The framework contains 12-membered ring channels along the  direction, within which [Co(dien)2]3+ ions are located. Each channel is enclosed by chiral interpenetrating double helices (see picture; dien=diethylenetriamine).
Wataru Sugimoto, Hideki Iwata, Yutaka Yasunaga, Yasushi Murakami and Yoshio Takasu
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200351691
A layered compound composed of crystalline ruthenic acid sheets interleaved with layers of water can be exfoliated (delaminated) to yield colloidal nanosheets. This material is a mixed conductor where the crystalline nanosheets contribute to the electron conductivity and the hydrous interlayer supplies proton transport (see diagram). A large active surface area and a high specific capacitance is promising for electrochemical supercapacitor applications.
Woo Sung Jeon, Albina Y. Ziganshina, Jae Wook Lee, Young Ho Ko, Jin-Koo Kang, Chongmok Lee and Kimoon Kim
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200351925
Picking up the thread: A large, reversible change in size as well as shape is observed in a pseudorotaxane-based molecular machine composed of cucurbituril (CB; bead) and a hexamethylene-bridged bisviologen (thread, see schematic representation) on application of external stimuli. The key feature of the machinelike behavior is the reversible formation of a molecular loop by intramolecular pairing of the terminal viologen radical cation units inside CB upon electrochemical or photochemical reduction.
Version of Record online: 5 SEP 2003 | DOI: 10.1002/anie.200390566