- Ag(i)/PPh3-catalyzed diastereoselective syntheses of spiro[indole-3,4′-piperidine] derivatives via cycloisomerizations of tryptamine-ynamides
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A Ag(i)/PPh3-catalyzed chelation-controlled cycloisomerization of tryptamine-ynamide was developed to access the spiro[indole-3,4′-piperidine] scaffold in a racemic and diastereoselective manner. The diastereoselective products were achieved by a chiron approach. Density functional theory (DFT) calculations indicated that strong non-covalent effects between the substrate and catalyst/ligand complex stabilized the spiroindoleninium intermediate via cation-π-π interactions.
- Chen, Yanyu,Cheng, Maosheng,Lin, Bin,Liu, Yongxiang,Sun, Shitao,Wang, Zhaobo,Yang, Lu,Zhang, Di,Zhang, Junpeng,Zhao, Wutong
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supporting information
p. 3051 - 3054
(2022/03/16)
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- Sequencing of Sequence-Defined Oligourethanes via Controlled Self-Immolation
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Sequence-defined polymers show promise for biomimetics, self-assembly, catalysis, and information storage, wherein the primary structure begets complex chemical processes. Here we report the solution-phase and the high-yielding solid-phase syntheses of discrete oligourethanes and methods for their self-immolative sequencing, resulting in rapid and robust characterization of this class of oligomers and polymers, without the use of MS/MS. Crucial to the sequencing is the inherent reactivity of the terminal alcohol to "unzip" the oligomers, in a controlled and iterative fashion, releasing each monomer as a 2-oxazolidinone. By monitoring the self-immolation reaction via LC/MS, an applied algorithm rapidly produces the sequence of the oligourethane. Not only does this process provide characterization of structurally complex molecules, it works as a reader of molecular information.
- Anslyn, Eric V.,Coronado, Jaime N.,Dahlhauser, Samuel D.,Escamilla, P. Rogelio,Glass, Samuel A.,Moor, Sarah R.,Rapagnani, Rachel M.,Saunders, Douglas P.,Shei, Jasper S.,Vandewalle, Abigail N.,York, Jordan T.
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supporting information
p. 2744 - 2749
(2020/03/10)
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- Visible-Light-Mediated Liberation and In Situ Conversion of Fluorophosgene
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The first example for the photocatalytic generation of a highly electrophilic intermediate that is not based on radical reactivity is reported. The single-electron reduction of bench-stable and commercially available 4-(trifluoromethoxy)benzonitrile by an organic photosensitizer leads to its fragmentation into fluorophosgene and benzonitrile. The in situ generated fluorophosgene was used for the preparation of carbonates, carbamates, and urea derivatives in moderate to excellent yields via an intramolecular cyclization reaction. Transient spectroscopic investigations suggest the formation of a catalyst charge-transfer complex-dimer as the catalytic active species. Fluorophosgene as a highly reactive intermediate, was indirectly detected via its next downstream carbonyl fluoride intermediate by NMR. Furthermore, detailed NMR analyses provided a comprehensive reaction mechanism including a water dependent off-cycle equilibrium.
- Petzold, Daniel,Nitschke, Philipp,Brandl, Fabian,Scheidler, Veronica,Dick, Bernhard,Gschwind, Ruth M.,K?nig, Burkhard
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supporting information
p. 361 - 366
(2018/11/23)
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- Catalytic fluoride triggers dehydrative oxazolidinone synthesis from CO2
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Herein, catalytic fluoride (F-) is demonstrated to be a trigger for dehydrative immobilization of atmospheric pressure CO2, such that reaction of CO2 with β-amino alcohols derived from natural amino acids gives optically pure oxazolidinones in high yields. A synergistic combination of fluoride and organosilicon agents (e.g., Bu4NF + Ph3SiF or siloxanes) enhances the catalytic activity and functional group compatibility. This system lies at the interface between homogenous and heterogeneous catalysis, and may prove useful for the development of recoverable/reusable siloxane-based CO2 immobilization materials. This journal is
- Takada, Yuki,Foo, Siong Wan,Yamazaki, Yusuke,Saito, Susumu
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p. 50851 - 50857
(2015/02/19)
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- Carbon dioxide as a carbonylating agent in the synthesis of 2-oxazolidinones, 2-oxazinones, and cyclic ureas: Scope and limitations
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Carbon dioxide can be used as a convenient carbonylating agent in the synthesis of 2-oxazolidinones, 2-oxazinones, and cyclic ureas. The transient carbamate anion generated by treating a primary or secondary amine group in basic media can be activated with phosphorylating agents such as Diphenylphosphoryl azide (DPPA) and Diphenyl chlorophosphate (DPPCl) but also with other types of electrophiles such as SOCl2, TsCl, or AcCl. The intramolecular trapping of the activated carbamate by a hydroxyl group leads to the formation of 2-oxazolidinones or 2-oxazinones in good to excellent yields. This methodology was successfully applied to the synthesis of cyclic ureas up to 7-membered rings from the corresponding diamines.
- Paz, Jairo,Perez-Balado, Carlos,Iglesias, Beatriz,Munoz, Luis
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experimental part
p. 3037 - 3046
(2010/07/15)
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- Synthesis of substituted-(l)-tryptophanols from an enantiomerically pure aziridine-2-methanol
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(Matrix Presented) Enantiomerically pure (l)-tryptophanol (5) was synthesized from 4(R)-iodomethyl-2-oxazolidinone (2) and indolylmagnesium bromide in three steps (52% overall yield). Using this procedure, we also prepared various tryptophanols with substituent(s) on the indole ring. Furthermore, optically active 4(R)-iodomethyl-2-oxazolidinone was readily prepared from an enantiomerically pure aziridine-2(S)-methanol in high yield.
- Pyun, Do Kyu,Lee, Cheol Hae,Ha, Hyun-Joon,Park, Chan Sun,Chang, Jae-Won,Lee, Won Koo
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p. 4197 - 4199
(2007/10/03)
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- Structure-activity relationship for DNA topoisomerase II-induced DNA cleavage by azatoxin analogues
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Eighteen analogues of the nonintercalative DNA topoisomerase II (topo II)-active epipodophyllotoxin-ellipticine hybrid, azatoxin, were synthesized and evaluated for their ability to induce topo II-mediated DNA strand breaks in vitro. In general, the SAR p
- Madalengoitia, Jose S.,Tepe, Jetze J.,Werbovetz, Karl A.,Lehnert, Erich K.,Macdonald, Timothy L.
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p. 1807 - 1815
(2007/10/03)
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- Topoisomerase II inhibitors and therapeutic uses therefor
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Azatoxin and derivatives thereof are illustrative of a new class of antitumor drugs that are topoisomerase II (top 2) inhibitors. The pharmacophore inhibits the catalytic activity of the purified enzyme but does not unwind relaxed or supercoiled DNA. It i
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- Inhibition of DNA topoisomerase II by azaelliptitoxins functionalized in the variable substituent domain
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A series of novel C11-substituted derivatives of azaelliptitoxin (azatoxin) have been synthesized and tested for their inhibitory activity against human DNA topoisomerase II. Incorporation of a C11 polyamine or amine resulted in an i
- Tepe, Jetze J.,Madalengoitia, Jose S.,Slunt, Kelli M.,Werbovetz, Karl W.,Spoors, P. Grant,Macdonald, Timothy L.
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p. 2188 - 2196
(2007/10/03)
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- A simple and efficient procedure for the preparation of chiral 2-oxazolidinones from α-amino acids
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A modified procedure for the title transformation is described which avoids: (i) a potentially hazardous borane reduction step, and (ii) the intermediacy of water soluble amino alcohols.
- Lewis,McKillop,Taylor,Watson
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p. 561 - 568
(2007/10/02)
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- Synthesis of New Chiral Auxiliaries Derived from (S)-Tryptophan
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The synthesis of chiral aminoalcohols 4 derived from (S)-tryptophan is described, by reaction of the protected amino acid 3 with various Grignard reagents.The aminoalcohols were transformed into the corresponding oxazolidin-2-ones 2 and acylated with 2-butenoyl chloride and 2-hexenoyl chloride, affording the imides 5a-e.The conformational analysis of both the oxazolidin-2-ones 2 and the Michael acceptors 5 was performed by means of 1H NMR, NOEDIF experiments and semiempirical AM1 calculations.
- Cardillo, Giuliana,Gentilucci, Luca,Tomasini, Claudia,Tomasoni, Laura
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p. 1947 - 1956
(2007/10/03)
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- A new approach to indole alkaloids via indole chromium complexes
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The activating effect of pi complexation of a Cr(CO)3 unit allows selective nucleophilic substitution in indoles such as tryptophan derivatives and provides intermediates for the synthesis of clavicipitic acid and related indole natural products.
- Semmelhack,Knochel,Singleton
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p. 5051 - 5054
(2007/10/02)
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