- Harnessing Secondary Coordination Sphere Interactions That Enable the Selective Amidation of Benzylic C-H Bonds
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Engineering site-selectivity is highly desirable especially in C-H functionalization reactions. We report a new catalyst platform that is highly selective for the amidation of benzylic C-H bonds controlled by π-πinteractions in the secondary coordination sphere. Mechanistic understanding of the previously developed iridium catalysts that showed poor regioselectivity gave rise to the recognition that the π-cloud of an aromatic fragment on the substrate can act as a formal directing group through an attractive noncovalent interaction with the bidentate ligand of the catalyst. On the basis of this mechanism-driven strategy, we developed a cationic (ν5-C5H5)Ru(II) catalyst with a neutral polypyridyl ligand to obtain record-setting benzylic selectivity in an intramolecular C-H lactamization in the presence of tertiary C-H bonds at the same distance. Experimental and computational techniques were integrated to identify the origin of this unprecedented benzylic selectivity, and robust linear free energy relationship between solvent polarity index and the measured site-selectivity was found to clearly corroborate that the solvophobic effect drives the selectivity. Generality of the reaction scope and applicability toward versatile γ-lactam synthesis were demonstrated.
- Jung, Hoimin,Schrader, Malte,Kim, Dongwook,Baik, Mu-Hyun,Park, Yoonsu,Chang, Sukbok
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supporting information
p. 15356 - 15366
(2019/10/22)
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- Intramolecular Friedel-Crafts Acylation Reaction Promoted by 1,1,1,3,3,3-Hexafluoro-2-propanol
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Simple dissolution of an arylalkyl acid chloride in 1,1,1,3,3,3-hexafluoro-2-propanol promotes an intramolecular Friedel-Crafts acylation without additional catalysts or reagents. This reaction is operationally trivial in both execution and product isolation (only requiring concentration followed by purification) and accommodates a broad range of substrates. Preliminary studies that bear upon potential reaction mechanisms are reported.
- Motiwala, Hashim F.,Vekariya, Rakesh H.,Aubé, Jeffrey
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supporting information
p. 5484 - 5487
(2015/11/18)
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- AZACYCLIC COMPOUNDS
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Compounds and methods are provided for the treatment of disease conditions in which modification of serotonergic receptor activity has a beneficial effect. In the method, an effective amount of a compound is adminstered to a patient in need of such treatment.
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Paragraph 0664
(2015/11/09)
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- A facile synthesis of pyrrolo-(di)-benzazocinones via an intramolecular N-acyliminium ion cyclisation
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A facile, moderate to high yielding synthesis of hexahydro-(di)- benzazocinones is described via an intramolecular N-acyliminium ion cyclisation. The iminium ion intermediates are formed from the readily available 4,4-diethoxybutyl amides with an excess of triflic acid. For electron-withdrawing substituents, better yields were obtained from the pre-formed 2-hydroxypyrrolidine amides. From NMR studies, at ambient temperatures the pyrrolo-benzazocin-3-ones exist as a slowly equilibrating mixture of two conformations.
- King, Frank D.,Aliev, Abil E.,Caddick, Stephen,Tocher, Derek A.,Courtier-Murias, Denis
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experimental part
p. 167 - 177
(2009/04/07)
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- USE OF 4-AMINO-PIPERIDINES FOR TREATING SLEEP DISORDERS
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Inverse agonists and antagonists of serotonin receptors are disclosed for use in treating sleep disorders such as insomnia, and specifically sleep maintenance insomnia. The compound increase slow wave sleep, decrease the number of awakenings after sleep onset, and decrease the time awake after sleep onset.
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Page/Page column 147-148
(2010/11/28)
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- The Meisenheimer Rearrangement in Heterocyclic Synthesis. II. Synthesis and X-Ray Crystal Structure of a Tetrahydro-1H-2,3-benzoxazocine and Preparation of a Hexahydro-2,3-benozoxazonine
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The heterocyclic derivatives, 8,9-dimethoxy-3-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-2,3-benzoxazocine (3a) and 9,10-dimethoxy-3-methyl-1-phenyl-1,3,4,5,6,7-hexahydro-2,3-benzoxazonine (3b), examples of two new ring systems, have been prepared by Meisenheimer rearrangement of the corresponding 2-benzazepine and 2-benzazocine N-oxide derivatives (2a) and (2b).The Bischler-Napieralski-type cyclization reaction was used in the preparation of the tertiary amine precursors of these N-oxides; reaction conditions for the cyclization were critical and phosphorus oxychloride inrefluxing butanenitrile was found to give the best yields of the seven- or eight-membered cyclic imine intermediates.Reductive cleavage of the benzoxazocine derivative (3a) with zinc in acetic acid followed by N-methylation gave the expected product, -4,5-dimethoxyphenyl>phenylmethanol (12).The crystal and molecular structure of (3a) has been determined by X-ray crystallographic analysis.
- Bremner, John B.,Browne, Elaine J.,Davies, Peter E.,Raston, Colin L.,White, Allan H.
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p. 1323 - 1334
(2007/10/02)
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