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1.
Takuya Hashimoto Dr. Kazuki Sakata Keiji Maruoka Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(27):5014-5017
Going through the phases : The title reaction was found to proceed by an initial base‐mediated isomerization to allenyl esters and subsequent phase transfer catalyzed alkylation at the α position of the ester (see scheme).
2.
Hai‐Hua Lu Hui Liu Dr. Wei Wu Xu‐Fan Wang Liang‐Qiu Lu Wen‐Jing Xiao Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(12):2742-2746
Economical approach : The first organocatalytic asymmetric intramolecular hydroarylation of phenol‐ and aniline‐derived enals offers one of the most straightforward and atom‐economic approaches to enantioriched chromans and tetrahydroquinolines (up to 96 % ee; see scheme).
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Andrew R. Shaffer Joseph A. R. Schmidt Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(11):2662-2673
Phorteen phine phosphines : Fourteen new α,β‐unsaturated β‐chloroimines were synthesized from inexpensive ketones by using the Vilsmeier–Haack reagent followed by Schiff‐base condensation. Each imine was subsequently converted to an α,β‐unsaturated 3‐iminophosphine through either late‐metal‐catalyzed phosphorus–carbon cross‐coupling or through an addition–elimination sequence (see scheme). This high‐yield protocol serves as a general means to produce α,β‐unsaturated 3‐iminophosphines.
4.
Yong‐beom Lim Dr. Kyung‐Soo Moon Myongsoo Lee Prof. 《Angewandte Chemie (International ed. in English)》2009,48(9):1601-1605
Protein roll call : Peptide‐based building blocks, in which both an α‐helix‐forming segment and a β‐sheet segment are located within a single macrocyclic structure, self‐assemble into α‐helix‐decorated artificial proteins. This approach provides a starting point for developing artificial proteins that can modulate α‐helix‐mediated interactions occurring in a multivalent fashion.
5.
Zhiyong Jiang Dr. Yuanyong Yang Yuanhang Pan Yujun Zhao Hongjun Liu Choon‐Hong Tan Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(19):4925-4930
Constructing α‐stereogenic amides and ketones : The highly regioselective and enantioselective conjugate addition of 1,3‐dicarbonyl compounds to 1,4‐dicarbonyl but‐2‐enes has been developed with the chiral bicyclic guanidine as catalyst (ee values up to 97 %; see scheme).
6.
A convenient route with high stereo control to γ‐acetoxy dienoates is provided by the reaction of methyl propiolate with aldehydes in the presence of ZnEt2 and N‐methylimidazole at room temperature, followed by the catalytic conversion of the resulting γ‐hydroxy‐α,β‐acetylenic esters with p‐N,N‐dimethylaminopyridine (DMAP) in acetic anhydride (see scheme).
7.
Toshiki Nokami Dr. Akito Shibuya Shino Manabe Dr. Yukishige Ito Dr. Jun‐ichi Yoshida Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(10):2252-2255
Low‐temperature electrochemical oxidation of thioglycosides gave glycosyl triflates from which glycosyl sulfonium ions were produced (see scheme). The latter were characterized by NMR spectroscopy and cold‐spray mass spectrometry as a mixture of α‐ and β‐isomers (45:55). The α‐glycosyl sulfonium ion exhibited higher reactivity than the β‐glycosyl sulfonium ion in the reaction with methanol, which gave a mixture of α‐ and β‐methyl glycosides (41:59).
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Romas Kudirka Sean K. J. Devine Christopher S. Adams David L. Van Vranken Prof. 《Angewandte Chemie (International ed. in English)》2009,48(20):3677-3680
As easy as 1, 2, 3 : A palladium‐catalyzed three‐component coupling generates α,β‐unsaturated γ‐amino acids in a single step (see scheme). The reaction is believed to involve migration of a vinyl substituent to a highly electrophilic palladium carbene. Unlike previous synthetic approaches, this synthesis provides access to γ‐amino acids with non‐natural side chains.
10.
Michiko Sasaki Dr. Hidaka Ikemoto Masatoshi Kawahata Dr. Kentaro Yamaguchi Prof. Kei Takeda Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(18):4663-4666
Don't get trapped : The effect of conjugating electron‐withdrawing groups and α‐anion‐stabilizing heteroatom substituents on configurational stability of chiral carbanions through a double bond was examined on the basis of extent of chirality transfer in intramolecular trapping in [2,3]‐Wittig rearrangement of chiral 3‐substituted 1‐propenyloxy‐1‐phenyl‐2‐propen‐1‐yl carbanions (see scheme).
11.
Paolo Melchiorre Dr. 《Angewandte Chemie (International ed. in English)》2009,48(8):1360-1363
Following the light: Photoredox catalysis along with aminocatalysis have proved to be the right combination for one of the most challenging asymmetric transformation in organic synthesis: the direct intermolecular α‐alkylation of aldehydes.
12.
Massimo Stefanoni Marco Luparia Dr. Alessio Porta Dr. Giuseppe Zanoni Dr. Giovanni Vidari Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(16):3940-3944
Rhenium does the job! A readily available rhenium complex efficiently catalyzed the direct Meyer–Schuster‐like rearrangement of different alkyl‐ and aryl‐substituted propargylic secondary and tertiary alcohols to the corresponding α,β‐unsaturated compounds, which were produced with virtually complete E stereoselectivity. The reaction proceeded under neutral conditions and no racemization of potentially enolizable stereocenters was observed.
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Halil Aktas J. Chris Slootweg Dr. Andreas W. Ehlers Dr. Martin Lutz Dr. Anthony L. Spek Prof. Dr. Koop Lammertsma Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(17):3108-3111
Do the twist : The reaction of in situ generated phosphinidenes with phosphaalkynes is a facile route to the new metal‐coordinated η3‐diphosphavinylcarbene 1 , which shows facile ligand‐exchange reactions and undergoes an unprecedented rearrangement that involves phosphinidene complex 2 and η3‐phosphaalkenylphosphinidene complex 3 , the 1,3 isomer of 1 .
15.
Huanhuan Liang Hao Chen Dr. Keqiang Fan Dr. Ping Wei Dr. Xianrong Guo Dr. Changwen Jin Prof. Chen Zeng Prof. Chao Tang Prof. Luhua Lai Prof. 《Angewandte Chemie (International ed. in English)》2009,48(18):3301-3303
A designer monomeric protein with a βαβ fold—two parallel β strands connected by an α helix (see structure)—was constructed solely from coded amino acids. The high thermal stability of the structure is due to a large extent to tryptophan–tryptophan interactions between the two β strands.
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17.
Taichi Ikeda Dr. Masayoshi Higuchi Dr. Dirk G. Kurth Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(19):4906-4913
Towards polythiophene polyrotaxanes : The β‐substituted terthiophene [2]rotaxanes have been synthesized (see figure). Basic optical and electrochemical properties of the synthesized [2]rotaxanes are also reported.
18.
Yann Ferrand Dr. Emmanuel Klein Dr. Nicholas P. Barwell Matthew P. Crump Dr. Jesus Jiménez‐Barbero Prof. Cristina Vicent Dr. Geert‐Jan Boons Prof. Sampat Ingale Anthony P. Davis Prof. 《Angewandte Chemie (International ed. in English)》2009,48(10):1775-1779
Changing employment : Receptor 1 binds β‐N‐acetylglucosaminyl (β‐GlcNAc) up to 100 times more strongly than it does glucose. This synthetic lectin shows affinities similar to wheat germ agglutinin (WGA), a natural lectin used to bind GlcNAc. Remarkably, 1 is more selective than WGA. It favors especially the glycoside unit in glycopeptide 2 , a model of the serine‐O‐GlcNAc posttranslational protein modification.
19.
Valeria Castelletto Dr. Ian W. Hamley Prof. Rohan A. Hule Dr. Darrin Pochan Prof. 《Angewandte Chemie (International ed. in English)》2009,48(13):2317-2320
An addition to the family : The introduction of β‐amino acid residues into a modified amyloid β peptide fragment resulted in well‐defined helical nanoribbons (see cryo‐TEM image) comprising β strands mainly oriented perpendicular to the ribbon axis. The nanoribbons order into a flow‐aligning nematic phase at higher concentration. The β‐strand nanoribbon structure is an addition to the known set of secondary structures adopted by β‐peptides.