- Photoredox-Catalyzed Cα-H Cyanation of Unactivated Secondary and Tertiary Aliphatic Amines: Late-Stage Functionalization and Mechanistic Studies
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This paper describes the development and mechanistic studies of a general, high-yielding amine Cα-H cyanation protocol via photoredox catalysis. Inexpensive NaCN is employed as the cyanide source and air is the external oxidant, resulting in mild and highly functional group tolerant conditions. Notably, efficient Cα-H cyanations of secondary and tertiary aliphatic amines and of complex, biologically active compounds (drugs) can be performed using the established methodology. Mechanistic studies suggest that the carboxylic acid additive has three effects: formation of a stabilizing hemiaminal intermediate, prevention of catalyst decomposition by protonating the substrate, and modulation of fluorescence quenching of the photoexcited catalyst species.
- Yilmaz, Ozgur,Oderinde, Martins S.,Emmert, Marion H.
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p. 11089 - 11100
(2018/09/12)
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- Iridium-Catalyzed Reductive Strecker Reaction for Late-Stage Amide and Lactam Cyanation
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A new iridium-catalyzed reductive Strecker reaction for the direct and efficient formation of α-amino nitrile products from a broad range of (hetero)aromatic and aliphatic tertiary amides, and N-alkyl lactams is reported. The protocol exploits the mild and highly chemoselective reduction of the amide and lactam functionalities using IrCl(CO)[P(C6H5)3]2 (Vaska's complex) in the presence of tetramethyldisiloxane, as a reductant, to directly generate hemiaminal species able to undergo substitution by cyanide upon treatment with TMSCN (TMS=trimethylsilyl). The protocol is simple to perform, broad in scope, efficient (up to 99 % yield), and has been successfully applied to the late-stage functionalization of amide- and lactam-containing drugs, and naturally occurring alkaloids, as well as for the selective cyanation of the carbonyl carbon atom linked to the N atom of proline residues within di- and tripeptides.
- Fuentes de Arriba, ángel L.,Lenci, Elena,Sonawane, Mahendra,Formery, Odilon,Dixon, Darren J.
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supporting information
p. 3655 - 3659
(2017/03/21)
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- Organocatalytic Glycosylation by Using Electron-Deficient Pyridinium Salts
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A new organocatalytic glycosylation method based on electron-deficient pyridinium salts is reported. At ambient temperature and catalyst loadings as low as 1 mol %, 2-deoxyglycosides were formed from benzyl- and silyl-protected glycals and primary or secondary glycosyl acceptors, with excellent yields and anomeric selectivity. Mechanistic investigations point to alcohol-pyridinium conjugates (1,2-addition products) as key intermediates in the catalytic cycle.
- Das, Somnath,Pekel, Daniel,Neud?rfl, J?rg-M.,Berkessel, Albrecht
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supporting information
p. 12479 - 12483
(2015/10/12)
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- POSITIVE RESIST COMPOSITION AND PATTERNING PROCESS
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A positive resist composition comprises (A) a resin component which becomes soluble in an alkaline developer under the action of an acid and (B) an acid generator. The resin (A) is a polymer comprising recurring units containing a non-leaving hydroxyl group represented by formula (1) wherein R1 is H, methyl or trifluoromethyl, X is a single bond or methylene, m is 1 or 2, and the hydroxyl group attaches to a secondary carbon atom. The composition is improved in resolution when processed by lithography.
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- Microwave-assisted beckmann rearrangement: Convenient synthesis of 1,3-diaza-bicyclo[3.2.2]nonane
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Small heterocyclic amines such as 1,3-diaza-bicyclo[3.2.2]nonane are known to be key components of biologically active molecules. A convenient synthesis of this compound utilizing a key Beckmann rearrangement of (Z)-1-aza-bicyclo[2.2. 2]octan-3-one oxime (6) with conc. H2SO4 under microwave irradiation was achieved. The desired compound (1) was obtained in 20% yield overall. Copyright Taylor & Francis LLC.
- Curtis, Michael P.,Bunnelle, William H.,Pagano, Thomas G.,Gopalakrishnan, Murali,Faghih, Ramin
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p. 321 - 326
(2007/10/03)
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- Novel tertiary (meth)acrylates having lactone structure, polymers, resist compositions and patterning process
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Novel tertiary (meth)acrylate compounds having a lactone structure are polymerizable into polymers having improved transparency, especially at the exposure wavelength of an excimer laser and dry etching resistance. Resist compositions comprising the polymers are sensitive to high-energy radiation, have a high resolution, and lend themselves to micropatterning with electron beams or deep-UV rays.
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- Amine compounds, resist compositions and patterning process
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Amine compounds having a cyano group are useful in resist compositions for preventing a resist film from thinning and also for enhancing the resolution and focus margin of resist.
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- Octahydro-indolizine and quinolizine and hexahydro-pyrrolizine
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The invention features substituted fused bicyclic compounds, pharmaceutical compositions containing them, and methods of using them to treat or prevent histamine-mediated diseases and conditions.
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- A New Method of α-Functionalization for Tertiary Amines by Nucleophilic Substitution of α-Siloxy Amines
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α-Siloxy amines, which were easily prepared by "silicon Polonovski reaction" of tertiary amine N-oxides with trialkylsilyl trifluoromethanesulfonate, were treated with various nucleophiles to give the corresponding α-functionalized tertiary amines in moderate to good yields.This new method has to the advantage that it enables the α-substitution of amines not only by alkyl groups but also by alkenyl and aryl groups with sp2 carbon as a reaction center, since the introduction of such groups is difficult in electrophilic substitution of dipole-stabilized α-lithio amines.Besides the organometallics such as Grignard and organoaluminum reagents, trimethylsilyl cyanide and silyl enol ether could also be employed as nucleophiles in the presence of an appropriate Lewis acid.
- Tokitoh, Norihiro,Okazaki, Renji
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p. 735 - 740
(2007/10/02)
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- A NEW SYNTHESIS OF α-CYANOAMINES. LEWIS ACID PROMOTED NUCLEOPHILIC SUBSTITUTION OF α-SILOXYAMINES USING TRIMETHYLSILYL CYANIDE
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α-Siloxyamines obtained from tertiary amines via their N-oxides were treated with titanium tetrachloride and trimethylsilyl cyanide to give α-cyanated tertiary amines in good yields.
- Tokitoh, Norihiro,Okazaki, Renji
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p. 241 - 242
(2007/10/02)
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