- Asymmetric induction during electron transfer mediated photoreduction of carbonyl compounds: Role of zeolites
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Photochemistry of 17 aryl alkyl ketones included within cation exchanged zeolites has been examined. In solution five of the 17 ketones undergo intramolecular hydrogen abstraction reaction even in the presence of a chiral amine and the rest are photoreduced to the corresponding alcohol. Within zeolites all 17 ketones yielded in presence of a chiral amine, the corresponding alcohol as the major product. When a chiral amine was used as the coadsorbent within alkali ion exchanged zeolites, enantiomerically enriched alcohol was formed in all cases. The best chiral induction was obtained with phenyl cyclohexyl ketone (enantiomeric excess: 68%). 1H-13C Cross Polarization Magic Angle Spinning (CP-MAS) experiments, with a model ketone (perdeuterated acetophenone) and chiral amine (pseudoephedrine) included within MY zeolites, suggested that the cation brings the reactant and the chiral amine closer. The role of the cation in such a process is also revealed by the computation results. The results presented here highlight the importance of a supramolecular structure in forcing a closer interaction between a reactant and a chiral inductor that could be used to achieve asymmetric induction in photoproducts. The Royal Society of Chemistry 2006.
- Shailaja,Kaanumalle, Lakshmi S.,Sivasubramanian, Karthikeyan,Natarajan, Arunkumar,Ponchot, Keith J.,Pradhan, Ajit,Ramamurthy
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- Enantioselective Radical Addition/Cross-Coupling of Organozinc Reagents, Alkyl Iodides, and Alkenyl Boron Reagents
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A hybrid transition-metal/radical process is described that results in the addition of organozinc reagents and alkyl halides across alkenyl boron reagents in an enantioselective catalytic fashion. The reaction can be accomplished both intermolecularly and intramolecularly, providing useful product yields and high enantioselectivities in both manifolds.
- Chierchia, Matteo,Xu, Peilin,Lovinger, Gabriel J.,Morken, James P.
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Read Online
- Ir(NHC)-Catalyzed Synthesis of β-Alkylated Alcohols via Borrowing Hydrogen Strategy: Influence of Bimetallic Structure
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Multi N-heterocyclic carbene(NHC)-modified iridium catalysts were employed in the β-alkylation of alcohols; dimerization of primary alcohols (Guerbet reaction), cross-coupling of secondary and primary alcohols, and intramolecular cyclization of alcohols. Mechanistic studies of Guerbet reaction, including kinetic experiments, mass analysis, and density functional theory (DFT) calculation, were employed to explain the fast reaction promoted by bimetallic catalysts, and the dramatic reactivity increase of monometallic catalysts at the late stage of the reaction. (Figure presented.).
- Sung, Kihyuk,Lee, Mi-hyun,Cheong, Yeon-Joo,Kim, Yu Kwon,Yu, Sungju,Jang, Hye-Young
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p. 3090 - 3097
(2021/05/10)
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- ARYLCYCLOHEXYLAMINE DERIVATIVES AND THEIR USE IN THE TREATMENT OF PSYCHIATRIC DISORDERS
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Provided herein are arylcyclohexylamine derivatives and their use in the treatment of psychiatric disorders.
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Paragraph 0311; 0312
(2021/07/02)
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- Reductive Arylation of Amides via a Nickel-Catalyzed Suzuki–Miyaura-Coupling and Transfer-Hydrogenation Cascade
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We report a means to achieve the addition of two disparate nucleophiles to the amide carbonyl carbon in a single operational step. Our method takes advantage of non-precious-metal catalysis and allows for the facile conversion of amides to chiral alcohols via a one-pot Suzuki–Miyaura cross-coupling/transfer-hydrogenation process. This study is anticipated to promote the development of new transformations that allow for the conversion of carboxylic acid derivatives to functional groups bearing stereogenic centers via cascade processes.
- Boit, Timothy B.,Mehta, Milauni M.,Kim, Junyong,Baker, Emma L.,Garg, Neil K.
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supporting information
p. 2472 - 2477
(2020/12/03)
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- Coupling Reaction between Aldehydes and Non-Activated Hydrocarbons via the Reductive Radical-Polar Crossover Pathway
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Herein, we describe the generation of an organochromium-type carbanion species from a non-activated C-H bond and its nucleophilic addition to aldehydes. The catalytic carbanion generation occurred through formal deprotonation of a non-activated C-H bond under mild conditions and did not need the prefunctionalization or anion stabilizing group. Carbon radical intermediates generated by decatungstate photocatalyst-mediated hydrogen abstraction were captured by a chromium salt with the reductive radical-polar crossover reaction to produce organochromium carbanions.
- Yahata, Kenzo,Sakurai, Shu,Hori, Shuhei,Yoshioka, Shin,Kaneko, Yuki,Hasegawa, Kai,Akai, Shuji
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supporting information
p. 1199 - 1203
(2020/02/04)
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- A General Method for Photocatalytic Decarboxylative Hydroxylation of Carboxylic Acids
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A general and practical method for decarboxylative hydroxylation of carboxylic acids was developed through visible light-induced photocatalysis using molecular oxygen as the green oxidant. The addition of NaBH4 to in situ reduce the unstable peroxyl radical intermediate much broadened the substrate scope. Different sp3 carbon-bearing carboxylic acids were successfully employed as substrates, including phenylacetic acid-type substrates, as well as aliphatic carboxylic acids. This transformation worked smoothly on primary, secondary, and tertiary carboxylic acids.
- Khan, Shah Nawaz,Zaman, Muhammad Kashif,Li, Ruining,Sun, Zhankui
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p. 5019 - 5026
(2020/05/01)
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- Covalently anchored chlorosulfonyl-calix[4]arene onto silica gel as an efficient and reusable heterogeneous system for reduction of ketones using NaBH4
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The catalytic activities of chlorosulfonyl-calix[4]arene-bonded silica gel (CSC[4]A-SG) as a novel heterogeneous catalyst was illustrated by efficient reduction of various ketones to their corresponding alcohols. To illustrate the promoting effect of the
- Chenari, Ashkan Bagheri,Saber-Tehrani, Mandana,Mamaghani, Manouchehr,Nikpassand, Mohammad
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- Alpha-cyclopentyl (phenyl) methanol synthesis and resolution method
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The invention discloses an alpha-cyclopentyl (phenyl) methanol synthesis and biological catalytic resolution method. The invention is specifically realized by the following operation: cyclopentyl phenyl ketone is taken as a raw material and reduced to obt
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Paragraph 0008
(2017/04/29)
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- Containing oxime substituent pyrazole piperidine ketone compound, and its composition and use thereof
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The invention relates to pyrazolopiperidone compounds, pharmaceutically-acceptable salts of the compounds and use of the compounds in preparation of medicines for treating Xa factor related diseases. Particularly, the invention relates to novel oxime substituent-containing pyrazolopiperidone compounds, pharmaceutical compositions containing the compounds and use of the compounds in the preparation of the medicines for treating the Xa factor related diseases.
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- Construction of cyclopentyl carbinols from ω-tosyloxy-1-alkenyl boronate esters and grignard reagents
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Addition of RMgCl (R = n-Bu, Ph) to pinacol esters of 6-tosyloxy-l-alkenyl boronic acids at -78 °C gave the borates, which upon warming to room temperature underwent migration of R on boron to C(1) carbon and concomitant ring construction C-C bond formati
- Kobayashi, Yuichi,Asano, Moriteru,Kiyotsuka, Yohei
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scheme or table
p. 787 - 791
(2010/09/18)
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- The "reverse-tethered" ruthenium (II) catalyst for asymmetric transfer hydrogenation: Further applications
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The attachment of a tethering group from the basic nitrogen atom to the arene ligand of a ruthenium(II) catalyst greatly improves its ability to catalyze asymmetric transfer hydrogenation (ATH) reactions. In this paper, we describe further applications of this versatile system to an extended substrate range.
- Morris, David J.,Hayes, Aidan M.,Wills, Martin
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p. 7035 - 7044
(2007/10/03)
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- Syntheses and Binding Studies of New [(Aryl)(aryloxy)methyl]piperidine Derivatives and Related Compounds as Potential Antidepressant Drugs with High Affinity for Serotonin (5-HT) and Norepinephrine (NE) Transporters
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In a wide search program toward new, efficient, and fast-acting antidepressant drugs, we have prepared series of new compounds having an (aryl)(aryloxy)methyl moiety linked directly or through a methylene chain to different substituted and unsubstituted cycles (isoquinoline, piperazine, piperidine, tetrahydropyran, or cyclopentane). These compounds have been evaluated for their affinities for serotonin (5-HT) transporter (SERT) and 5-HT1A and 5-HT2A receptors. Racemic mixtures of 4-[(aryl)(aryloxy)methyl]piperidine derivatives showed much higher affinity values for SERT than fluoxetine and resulted in lack of affinity for 5-HT 1A and 5-HT2A receptors. Some of these racemic mixtures were resolved to their enantiomers and tested for binding to norepinephrine (NE) transporter (NET), dopamine (DA) transporter (DAT), and α2 receptor. Several of these enantiomers [(-)-15b, (-)-15j, (-)-15t, (+)-15u] displayed a dual binding profile with affinities for SERT and NET with K i i = 1.9 and 13.5 nM, respectively), and further pharmacological characterization is in progress for its evaluation as a antidepressant.
- Orjales, Aurelio,Mosquera, Ramón,Toledo, Antonio,Pumar, M. Carmen,García, Neftalí,Cortizo, Lourdes,Labeaga, Luis,Innerárity, Ana
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p. 5512 - 5532
(2007/10/03)
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- A new method for alkylation of aromatic aldehydes using alkylboron chloride derivatives in the presence of oxygen
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Reactions of aromatic aldehydes with alkylboron chloride derivatives in the presence of oxygen have been investigated. Dialkylboron chlorides react with aryl aldehydes to produce arylalkylmethanols in good to excellent yields. Under the same reaction conditions, alkylboron dichlorides lead to the formation of arylalkyl chlorides.
- Kabalka, George W,Wu, Zhongzhi,Ju, Yuhong
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p. 3243 - 3248
(2007/10/03)
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- Alkylation of aromatic aldehydes with alkylboron chloride derivatives
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The reaction of aryl aldehydes with alkylboron chlorides has been investigated. Monoalkylboron dichlorides react with aryl aldehydes in hexane under reflux conditions to give a mixture of dichloroarylmethane and benzyl chloride. Under the same reaction conditions, dialkylboron chlorides lead to formation of a mixture of benzyl chloride and the chloroalkylation product. In the presence of a base such as 2,6-lutidine, the reactions of monoalkylboron dichlorides with aryl aldehydes yield small amounts of the desired alkylation products at room temperature. Dialkylboron chlorides react with aryl aldehydes in hexane in the presence of base to generate the corresponding arylalkylmethanols in good yields.
- Kabalka, George W,Wu, Zhongzhi,Ju, Yuhong
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p. 1663 - 1670
(2007/10/03)
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- Oxidative decarboxylation of arylacetic acids mediated by peroxysulfur intermediate generated from 2-nitrobenzenesulfonyl chloride and superoxide
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The oxidative decarboxylation of aryl, α, α-diaryl, or arylalkylacetic acids has been achieved by a 2-nitrobenzenesulfonyl peroxy radical intermediate (I) generated by the reaction of 2-nitrobenzenesulfonyl chloride with potassium superoxide at -20°C in dry acetonitrile.
- Kim II, Yong,Kim, Yong Hae
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p. 639 - 642
(2007/10/03)
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