- Ruthenium-catalyzed intramolecular arene C(sp2)-H amidation for synthesis of 3,4-dihydroquinolin-2(1 H)-ones
-
We report the [Ru(p-cymene)(l-proline)Cl] ([Ru1])-catalyzed cyclization of 1,4,2-dioxazol-5-ones to form dihydroquinoline-2-ones in excellent yields with excellent regioselectivity via a formal intramolecular arene C(sp2)-H amidation. The reactions of the 2- and 4-substituted aryl dioxazolones proceeds initially through spirolactamization via electrophilic amidation at the arene site, which is para or ortho to the substituent. A Hammett correlation study showed that the spirolactamization is likely to occur by electrophilic nitrenoid attack at the arene, which is characterized by a negative ρ value of -0.73.
- Au, Chi-Ming,Ling, Cho-Hon,Sun, Wenlong,Yu, Wing-Yiu
-
supporting information
p. 3310 - 3314
(2021/05/29)
-
- Quantitative Analysis on Two-Point Ligand Modulation of Iridium Catalysts for Chemodivergent C-H Amidation
-
The transition-metal-catalyzed nitrenoid transfer reaction is one of the most attractive methods for installing a new C-N bond into diverse reactive units. While numerous selective aminations are known, understanding complex structural effects of the key intermediates on the observed chemoselectivity is still elusive in most cases. Herein, we report a designing approach to enable selective nitrenoid transfer leading to sp2 spirocyclization and sp3 C-H insertion by cooperative two-point modulation of ligands in the CpXIr(III)(κ2-chelate) catalyst system. Computational analysis led us to interrogate structural motifs that can be attributed to the desired mechanistic dichotomy. Multivariate linear regression analysis on the perturbation on the η5-cyclopentadienyl ancillary (CpX) and LX coligand, wherein we prepared over than 40 new catalysts for screening, allowed for construction of an intuitive yet robust statistical model that predicts a large set of chemoselective outcomes, implying that the catalysts' structural effects play a critical role on the chemoselective nitrenoid transfer. On the basis of this quantitative analysis, a new catalytic platform is now established for the unique lactam formation, leading to the unprecedented chemoselective reactivity (up to >20:1) toward a diverse array of competing sites, such as tertiary, secondary, benzylic, allylic C-H bonds, and aromatic πsystem.
- Hwang, Yeongyu,Jung, Hoimin,Lee, Euijae,Kim, Dongwook,Chang, Sukbok
-
supporting information
p. 8880 - 8889
(2020/12/23)
-
- Construction of enantioenriched 9H-Fluorene frameworks via a cascade reaction involving remote vinylogous dynamic kinetic resolution
-
The benzylic C-H group of α,α-dicyanoolefins from 3-substituted 1-indanones could be significantly activated via transmission along the aromatic system, thus enabling dynamic kinetic resolution via a traditional reversible deprotonation- protonation process. Enantioenriched 9-substituted 9H-fluorene frameworks were finally constructed through an asymmetric vinylogous Michael addition to nitroolefins, followed by a cascade cyclization and oxidative aromatization process, under the catalysis of a chiral bifunctional thiourea-tertiary amine.
- Hu, Cui-Xia,Chen, Lin,Hu, Di,Song, Xue,Chen, Zhi-Chao,Du, Wei,Chen, Ying-Chun
-
supporting information
p. 8973 - 8977
(2020/11/30)
-
- Identification of an Esterase Isolated Using Metagenomic Technology which Displays an Unusual Substrate Scope and its Characterisation as an Enantioselective Biocatalyst
-
Evaluation of an esterase annotated as 26D isolated from a marine metagenomic library is described. Esterase 26D was found to have a unique substrate scope, including synthetic transformations which could not be readily effected in a synthetically useful manner using commercially available enzymes. Esterase 26D was more selective towards substrates which had larger, more sterically demanding substituents (i. e. iso-propyl or tert-butyl groups) on the β-carbon, which is in contrast to previously tested commercially available enzymes which displayed a preference for substrates with sterically less demanding substituents (e.g. methyl group) at the β-carbon. (Figure presented.).
- Gavin, Declan P.,Murphy, Edel J.,Foley, Aoife M.,Castilla, Ignacio Abreu,Reen, F. Jerry,Woods, David F.,Collins, Stuart G.,O'Gara, Fergal,Maguire, Anita R.
-
supporting information
p. 2466 - 2474
(2019/03/11)
-
- Stereoselective Sulfinyl Aniline-Promoted Pd-Catalyzed C?H Arylation and Acetoxylation of Aliphatic Amides
-
Stereoselective functionalization of aliphatic C?H bonds presents a great challenge. Following this target, we disclose herein an original strategy towards direct arylation of aliphatic chains at ?-methylene position based on a use of amide-sulfoxide bicoordinating directing group. Although moderate to high chiral induction (up to 9:1 d.r.) is achieved, diastereomerically pure compounds may be afforded by simple separation of diastereomeric products by silica gel chromatography. Accordingly, this reaction allows preparation of a large scope of high-value scaffolds in synthetically useful yields while recyclable character of our chiral auxiliary brings an additional benefit. A potential of this methodology to build up original molecules by sequential diarylation and expedient (two step) synthesis of a biologically active compound are further disclosed. Finally a first example of stereoselective direct acetoxylation of aliphatic chains is reported.
- Jerhaoui, Soufyan,Djukic, Jean-Pierre,Wencel-Delord, Joanna,Colobert, Fran?oise
-
supporting information
p. 15594 - 15600
(2017/10/20)
-
- Direct β-Selective Hydrocarboxylation of Styrenes with CO2 Enabled by Continuous Flow Photoredox Catalysis
-
The direct β-selective hydrocarboxylation of styrenes under atmospheric pressure of CO2 has been developed using photoredox catalysis in continuous flow. The scope of this methodology was demonstrated with a range of functionalized terminal styrenes, as well as α-substituted and β-substituted styrenes.
- Seo, Hyowon,Liu, Aofei,Jamison, Timothy F.
-
supporting information
p. 13969 - 13972
(2017/10/17)
-
- Lipase catalysed kinetic resolutions of 3-aryl alkanoic acids
-
Hydrolase catalysed kinetic resolutions leading to a series of 3-aryl alkanoic acids (≥94% ee) are described. Hydrolysis of the ethyl esters with a series of hydrolases was undertaken to identify biocatalysts that yield the corresponding acids with excellent enantiopurity in each case. Steric and electronic effects on the efficiency and enantioselectivity of the biocatalytic transformation were also explored.
- Deasy, Rebecca E.,Brossat, Maude,Moody, Thomas S.,Maguire, Anita R.
-
experimental part
p. 47 - 61
(2011/04/18)
-
- Lipase catalyzed acylation of primary alcohols with remotely located stereogenic centres: the resolution of (±)-4,4-dimethyl-3-phenyl-1-pentanol
-
Enantioselective acylation of some (±)-3-alkyl-3-phenyl-1-propanols was performed with enzymes as catalysts. Moderate enantiomeric ratios (E), ranging up to E = 11.6, were obtained. In the resolution, some of the lipases selectively acylated the (+)-enant
- Sabbani, Sunil,Hedenstroem, Erik,Andersson, Jimmy
-
p. 1712 - 1720
(2008/02/11)
-
- NITROGENOUS CYCLIC COMPOUNDS AND PHARMACEUTICAL COMPOSITIONS CONTAINING THE SAME
-
The present invention provides a novel compound having a superior calcium antagonism, in particular, a neuron-selective calcium antagonism. Namely, it provides a compound represented by the following formula, a salt thereof or a hydrate of them. In the formula, Ar indicates an optionally substituted 5- to 14-membered aromatic ring etc.; the ring A indicates any one ring selected from a piperazine, a homopiperazine, a piperidine and the like; the ring B indicates an optionally substituted C3-14 hydrocarbon ring etc.; E indicates a single bond, a group represented by the formula -CO-, etc.; X indicates a single bond, an oxygen atom etc.; R1 indicates a hydrogen atom, a halogen atom, a hydroxyl group etc.; and D1, D2, W1 and W2 are the same as or different from each other and each represents a single bond or an optionally substituted C1-6 alkylene chain.
- -
-
-
- Enantioselective conjugate radical addition reactions mediated by chiral Lewis acid complexes of (R,R)-4,6-dibenzofurandiyl-2,2'-bis(4- phenyloxazoline) (DBFOX/Ph)
-
A high-yielding synthesis (50% overall yield) of tridentate bisoxazoline ligand (R,R)-4,6-dibenzofurandiyl-2,2'-bis(4-phenyloxazoline) (DBFOX/Ph) was developed. DBFOX/Ph was subsequently tested in enantioselective conjugate radical additions onto 3-(3-phe
- Iserloh, Ulrich,Curran, Dennis P.,Kanemasa, Shuji
-
p. 2417 - 2428
(2007/10/03)
-
- Stereocontrol in the intramolecular Buchner reaction of diazoketones
-
Rhodium(II) acetate catalysed intramolecular Buchner cyclisation of a series of diazoketones 1 proceeds with excellent diastereoselectivity to produce the trans substituted azulenones 2, which exist as a rapidly equilibrating cycloheptatriene-norcaradiene system, from which the norcaradiene tautomers can be efficiently trapped as PTAD cycloadducts 4. The cyclisation-cycloaddition sequence can be conducted in either a stepwise or a tandem process, leading to the pentacyclic systems 4 as a single diastereomer in each case. In the reaction of diazoketone If intramolecular cyclopropanation competes with cyclisation to the aromatic ring.
- Maguire, Anita R.,Buckley, N. Rachael,O'Leary, Patrick,Ferguson, George
-
p. 4077 - 4091
(2007/10/03)
-
- Remarkable dependence of the regioselectivity of free radical additions to 3-cinnamoyloxazolidin-2-ones on the stability of the intermediate adduct-radical, electrophilicity of the adding radicals and the conditions for their generation
-
Electrophilic (CCl3) and nucleophilic radicals (Pri) are found to add at 80°C to the C=C bond of 3-(E)-cinnamoyl-4-phenyloxazolidin-2-one 1a and 3-(E)-cinnamoyl-4-benzyloxazolidin-2-one 1b predominantly at the α-position of the bond. While for the CCl3 radical no product of β-addition has been found, for the Pri radical such a path constitutes up to 40% of the whole process at 80°C. An interplay between the stability of the intermediate adduct radicals and the electrophilicity or nucleophilicity of the radicals undergoing addition are invoked to rationalize the observation. At a low temperature (-23°C) β-addition of the Pri radical becomes the dominant process (up to 75%).
- Tararov, Vitali I.,Kuznetzov, Nikolai Yu.,Bakhmutov, Vladimir I.,Ikonnikov, Nikolai S.,Bubnov, Yuri N.,Khrustalev, Victor N.,Saveleva, Tatiana F.,Belokon, Yuri N.
-
p. 3101 - 3106
(2007/10/03)
-
- Asymmetric synthesis of optically pure β-isopropylphenylalanine: A new β-branched unusual amino acid
-
All four optically pure isomers of a highly conformationally constrained unusual amino acid, β-isopropylphenylalanine, have been asymmetrically synthesized.
- Liao, Subo,Hruby, Victor J.
-
p. 1563 - 1566
(2007/10/03)
-
- 1,2-Secopyrethroids: Synthesis of (+/-) α-(RS)-cyano-3-phenoxybenzyl-4-methyl-3-phenyl/p-substituted-phenylpentanoates
-
A simple, elegant synthesis of (+/-) α-(RS)-cyano-3-phenoxybenzyl-4-methyl-3-phenyl/p-substituted-phenylpentanoates (I,XIV,XXI) has been described.
- Kher, S. M.,Kulkarni, G. H.
-
p. 675 - 676
(2007/10/02)
-
- Asymmetric Alkylation of a Chiral α-Amino Alkenenitrile
-
Alkylation of the unsymmetric allylic anion generated from 2-(L-ephedrino)-4-phenylbut-3-enenitrile occurred exclusively at C-4 to give predominantly products having the 4R-configuration ; the stereoselectivity increased remarkably when the reaction was conducted in a mixture of hexamethylphosphoramide and lithium iodide.
- Fang, Jim-Min,Chang, Chih-Jung
-
p. 1787 - 1788
(2007/10/02)
-
- Steric Effects in the Synthesis of 1,7-Dialkylindans
-
Synthesis routes to 1-alkyl(CH3,C2H5,i-C3H7)-6-methylindans and 1-alkyl(CH3,C2H5,i-C3H7)-7-methylindans are described.Members of the latter series, especially 1-isopropyl-7-methylindan, are sterically hindered through a peri interaction.This effect manifests itself throughout the study and necessitated use of alternative synthesis routes.Yields in the Grignard, Peterson olefination, Reformatsky, and Wittig reactions as well as catalytic hydrogenation and Li/NH3 reduction of α,β-unsaturated acids were compared.
- Budhram, Ronald S.,Palaniswamy, Ventakapuran A.,Eisenbraun, Edmund J.
-
p. 1402 - 1406
(2007/10/02)
-
- RING OPENING AND RING ENLARGEMENT OF A CYCLOPROPENE CARBOXYLIC ACID
-
3,3-Dimethyl-2-phenyl-cyclopropenecarboxylic acid 4 is prepared, starting with chlorophenyldiazirine 1.With acids 4 yields the open chain carboxylic acids 5, 6 and 7.Thionylchloride leads to the cyclobutenone 10, DCC to the acid anhydrides 11 and 13.
- Schmitz, E.,Sonnenschein, H.,Kuban, R. J.
-
p. 4911 - 4914
(2007/10/02)
-
- Synthese de methoxycarbonylindenes, dihydro-1,2 naphtalenes et benzocycloheptene. Obtention des indanones-1, des tetralones-1 et de la benzosuberone correspondantes
-
The synthesis of methoxycarbonylindenes, 1,2-dihydro-naphtalenes, and benzocycloheptene starting from the corresponding 1-indanones, 1-tetralones, and benzosuberone is reported.The starting ketones were synthesized by methods described in the literature which were optimized; in some cases new processes are described.
- Verbel, Joel,Carrie, Robert
-
p. 116 - 124
(2007/10/02)
-
- Silyl Phosphites. XVIII. Versatile Utility of α-(Trimethylsilyloxy)-alkylphosphonates as Key Intermediates for Transformation of Aldehydes into Several Carbonyl Derivatives
-
Carbonyl addition compounds of diethyl trimethylsilyl phosphite (DTMSP) with aldehydes were converted, by treatment with lithium diisopropylamide (LDA) followed by the successive alkylation and alkaline hydrolysis, to carbonyl derivatives involving aldehydes, unsymmetrical ketones, β,γ-unsaturated ketones, and carboxylic acids. β-Substituted carboxylic esters and γ-substituted lactones were prepared by use of the carbonyl addition compounds of DTMSP with α,β-unsaturated aldehydes.
- Sekine, Mitsuo,Nakajima, Masashi,Kume, Akiko,Hashizume, Akio,Hata, Tsujiaki
-
p. 224 - 238
(2007/10/02)
-