- Highly Enantioselective Iridium-Catalyzed Hydrogenation of Conjugated Trisubstituted Enones
-
Asymmetric hydrogenation of conjugated enones is one of the most efficient and straightforward methods to prepare optically active ketones. In this study, chiral bidentate Ir-N,P complexes were utilized to access these scaffolds for ketones bearing the stereogenic center at both the α- and β-positions. Excellent enantiomeric excesses, of up to 99%, were obtained, accompanied with good to high isolated yields. Challenging dialkyl substituted substrates, which are difficult to hydrogenate with satisfactory chiral induction, were hydrogenated in a highly enantioselective fashion.
- Peters, Bram B. C.,Jongcharoenkamol, Jira,Krajangsri, Suppachai,Andersson, Pher G.
-
supporting information
p. 242 - 246
(2021/01/13)
-
- Redox-Neutral Cobalt(III)-Catalyzed C-H Activation/Annulation of α,β-Unsaturated Oxime Ether with Alkyne: One-Step Access to Multisubstituted Pyridine
-
A redox neutral Co(III)-catalyzed annulation of α,β-unsaturated oxime ether with alkyne has been reported. Multisubstituted pyridines were synthesized in good yields without the use of any heavy metal oxidants. The developed methodology tolerates a variety of functional groups. Notably, this transformation has been applied to the late-stage modification of the bioactive molecule dehydropregnenolone.
- Mohanty, Smruti Ranjan,Pati, Bedadyuti Vedvyas,Banjare, Shyam Kumar,Das Adhikari, Gopal Krushna,Ravikumar, Ponneri Chandrababu
-
p. 1074 - 1083
(2021/01/14)
-
- Ruthenium-catalysed synthesis of chiral exocyclic allylic alcoholsviachemoselective transfer hydrogenation of 2-arylidene cycloalkanones
-
An exclusive asymmetric reduction of C=O bonds of 2-arylidene four-, five-, six-, and seven-membered cycloalkanones has been studied systematically. The asymmetric transfer hydrogenation was performed using a robust and commercially available chiral diamine-derived ruthenium complex as a catalyst and HCOOH/Et3N as a hydrogen source under mild conditions, giving 51 examples of chiral exocyclic allylic alcohols in up to 96% yield and 99% ee. This method was also applicable to the gram-scale synthesis of the active intermediates of the anti-inflammatory loxoprofen and natural product (?)-goniomitine.
- Zhang, Kaili,Liu, Qixing,He, Renke,Chen, Danyi,Deng, Zhangshuang,Huang, Nianyu,Zhou, Haifeng
-
supporting information
p. 1628 - 1632
(2021/03/09)
-
- Activated charcoal-mediated synthesis of chalcones catalyzed by NaOH in water
-
A variety of chalcones were synthesized in good yields by the activated charcoal-mediated aldol reactions between benzaldehydes and acetophenones catalyzed by NaOH in water. 2,6-Bis((E)-benzylidene)cyclohexan-1-ones were prepared by the aldol reactions between benzaldehydes and cyclohexanone. Activated charcoal could be recycled five times without the significant decrease of yields.
- Tanemura, Kiyoshi,Rohand, Taoufik
-
-
- Rhodium-catalyzed asymmetric hydrogenation of exocyclic α,β-unsaturated carbonyl compounds
-
A highly enantioselective hydrogenation of exocyclic α,β-unsaturated carbonyl compounds catalyzed by Rh/bisphosphine-thiourea (ZhaoPhos) has been developed, giving the corresponding α-chiral cyclic lactones, lactams and ketones with high yields and excellent enantioselectivities (up to 99% yield and 99% ee). Remarkably, the hydrogen bond between the substrate and the catalyst plays a critical role in this transformation. The synthetic utility of this protocol has been demonstrated by efficient synthesis of chiral 3-(4-fluorobenzyl)piperidine, a key chiral fragment of bioactive molecules.
- Yang, Jiaxin,Li, Xiuxiu,You, Cai,Li, Shuailong,Guan, Yu-Qing,Lv, Hui,Zhang, Xumu
-
supporting information
p. 856 - 859
(2020/02/15)
-
- Novel chalcones derivatives with potential antineoplastic activity investigated by docking and molecular dynamics simulations
-
Glioblastoma is an aggressive primary tumor of the central nervous system (CNS). Is the most aggressive among infiltrative gliomas arising from the CNS. This tumor has low patient survival rate and several studies aiming at developing new drugs have increased. Patients with this cancer type face significant morbidity and mortality. This study evaluated the antineoplastic activity of synthetic chalcones (3a-3f) using in vitro glioblastoma models and molecular modeling. Cytotoxicity assay showed that Astrocitoma Hospital Ofir Loyola No 1 (AHOL1) and Uppsala 87 neoplastic glioblastoma lines (U87) cellular viability were significantly reduced compared to Healthy human fibroblasts cell lines (AN27) when exposed to chalcones. Interaction with the serine amino acid was present in the most promising and the reference binder docking, suggesting its importance inhibiting cell growth. Comparative analysis between the reference ligands and the molecules showed that the amino acid LYS352 present in all fittings, suggesting that this is the main amino acid for interaction with tubulin and are consistent with those in cytotoxicity assay, suggesting antineoplastic potential in glioblastoma. Long trajectory molecular dynamics studies were also carried out in order to investigate stability and conformations amongst the chalcones bound tubulin as well, in comparison to doxorubicin (here used as control), however future studies are needed to further assess the mechanism of inhibition of chalcones used in this investigation. Communicated by Ramaswamy H. Sarma.
- Neto, Raimundo de A. M.,Santos, Cleydson B. R.,Henriques, Shayanne V. C.,Machado, Letícia de O.,Cruz, Jorddy N.,da Silva, Carlos H. T. de P.,Federico, Leonardo B.,Oliveira, Edivaldo H. C. de,de Souza, Michel P. C.,da Silva, Patrícia N. B.,Taft, Carlton A.,Ferreira, Irlon M.,Gomes, Madson R. F.
-
-
- Synthesis of hexahydrophenanthridines via the tandem reaction of benzynes
-
A tandem insertion-cyclization reaction between carbocyclic β–amino ketones and benzynes has been described, producing hexahydrophenanthridines in moderate to high yields.
- Li, Wen-Juan,Pian, Ji-Xin,Gu, Cheng-Zhi,Dai, Bin,He, Lin
-
-
- Novel racemic chiral organic boron nitrogen fluorescent compound and preparation method thereof (by machine translation)
-
The novel chiral organic boron nitride fluorescent compound, is characterized in that, takes a cheap,readily available monoiodobenzene derivative, carboxylic acid derivative as a raw material, to react at a certain temperature with a common organic solvent as a reaction solvent, for a certain time, high yield, to selectively obtain a novel chiral organic boron nitrogen fluorescent compound . The catalyst, can be recovered, at a certain temperature for a certain period of time for a certain period of time to produce a novel chiral organic boron-nitrogen fluorescent compound with low cost,and a high yield, and selectivity, can be, obtained at a certain temperature for a certain period, of time with a certain period of time and high yield. (by machine translation)
- -
-
Paragraph 0118-0125
(2020/05/05)
-
- Establishing the correlation between catalytic performance and N→Sb donor-acceptor interaction: Systematic assessment of azastibocine halide derivatives as water tolerant Lewis acids
-
A series of organoantimony(iii) halide complexes with a tetrahydrodibenzo[c,f][1,5]azastibocine framework were synthesized and employed as water tolerant Lewis acid catalysts. The results of a systematic structure-activity relationship study demonstrated that the strength of N→Sb donor-acceptor interaction could be synergistically modulated by tuning the properties of the nitrogen substituents and halogen atoms adjacent to the central antimony atom, and consequently resulted in distinct catalytic performances towards organic reactions such as Mannich, cross-condensation, cyclization-aromatization and epoxide aminolysis reaction. The fluorinated organoantimony(iii) derivatives were found to be more active than those of the chlorinated, brominated and iodinated analogues, owing to the use of an Sb-F moiety as a hydrogen bond acceptor. By comparison, the compound 6-cyclohexyl-12-fluoro-5,6,7,12-tetrahydrodibenzo[c,f][1,5] azastibocine (1d) is found to exhibit the highest catalytic activity, together with facile reusability in scale enlarged synthesis.
- Lei, Jian,Peng, Lingteng,Qiu, Renhua,Liu, Yongping,Chen, Yi,Au, Chak-Tong,Yin, Shuang-Feng
-
supporting information
p. 8478 - 8487
(2019/06/19)
-
- Green synthesis of dissymmetric bisarylidene derivatives of cyclohexanone analogues under ultrasonic conditions
-
Abstract: A new procedure is developed for the synthesis of dissymmetric bisarylidene derivatives of two cyclohexanone analogues. Under mild ultrasonic/organocatalytic conditions, the first aldehyde reacts with the ketone to give the monoarylidene intermediate which subsequently condenses with the second aldehyde upon addition of NaOH/MeOH to the reaction mixture. Both condensations proceed in one pot, and high yields of the corresponding products are obtained in relatively short time periods. It was shown that the method is useful for the synthesis of monoarylidene counterparts as well. Graphical abstract: [Figure not available: see fulltext.].
- Mojtahedi, Mohammad M.,Afshinpoor, Leila,Karimi, Fatemeh,Abaee, M. Saeed
-
p. 209 - 217
(2019/01/30)
-
- RuPHOX-Ru-Catalyzed Selective Asymmetric Hydrogenation of Exocyclic α,β-Unsaturated Pentanones
-
A RuPHOX-Ru catalyzed selective asymmetric hydrogenation of exocyclic α,β-unsaturated ketones has been developed, furnishing the corresponding chiral exocyclic allylic alcohols in high yields and with up to >99.5percent ee. The reaction could be performed on a gram scale with a relatively low catalyst loading (up to 10000 S/C) without any loss in reaction activity and enantioselectivity. The resulting hydrogenated products could be easily transformed to several biologically active compounds with high asymmetric performance. The asymmetric protocol provides an efficient methodology for the synthesis of chiral exocyclic allylic alcohols.
- Li, Jing,Liu, Delong,Liu, Yangang,Lu, Yufei,Wang, Yanzhao,Zhang, Wanbin,Zhu, Yue
-
supporting information
(2019/08/26)
-
- Stereodivergent Access to Enantioenriched Epoxy Alcohols with Three Stereogenic Centers via Ruthenium-Catalyzed Transfer Hydrogenation
-
The resolution technique of stereodivergent reaction on racemic mixtures (stereodivergent RRM) was employed for the first time in ruthenium complex catalyzed transfer hydrogenation of racemic epoxy ketones, providing a new and very simple method that allows access to enantioenriched epoxy alcohols with three stereogenic centers in a one-step fashion. The protocol features simple reaction conditions, practical operation, ability to scale up, and broad group tolerance.
- Zhao, Zhifei,Bagdi, Prasanta Ray,Yang, Shuang,Liu, Jinggong,Xu, Weici,Fang, Xinqiang
-
supporting information
p. 5491 - 5494
(2019/08/01)
-
- An access to α, β-unsaturated ketones via dual cooperative catalysis
-
A dual cooperative organocatalytic approach for the synthesis of α, β-unsaturated ketones is described. This one pot transformation is realized via a domino Knoevenagel-Michael-retro Michael reaction sequence. Various aliphatic ketones reacted smoothly with aromatic as well as aliphatic aldehydes in presence catalytic amount of Meldrum's acid and bifunctional amine. The highlights of this protocol are the easy availability of catalysts, high selectivity, and functional group tolerance. The reaction proved to highly E-selective with no side products emanating from self-condensation, unlike the base-mediated reactions.
- Syamala, Lakshmi V.R. Babu,Khopade, Tushar M.,Warghude, Prakash K.,Bhat, Ramakrishna G.
-
supporting information
p. 88 - 91
(2018/12/05)
-
- Bovine serum albumin-catalysed cross aldol condensation: Influence of ketone structure
-
Bovine serum albumin (BSA) catalyses the cross aldol condensation and proved to be catalytically active at mild temperature and in ethanol, a cheap and green solvent, contrasting with the strong or expensive reaction media usually employed for this reaction. We herein report the reaction of a set of ketones (butanone, 3-pentanone, cyclopentanone and cyclohexanone) with benzaldehyde and p-nitrobenzaldehyde which provided high conversions (77–95%) of the corresponding enones (isolated in a range of yields from 19% to 74%). Parameters assayed to achieve these conversion values were solvent, ketone/aldehyde molar ratio and temperature. In this procedure only cyclohexanone gave the bis-enone, by-product of the conventional aldol condensation, in low amount even at high benzaldehyde/cyclohexanone molar excess. Under the assayed conditions null or low ketol amounts were observed, except for the reaction of cyclopentanone and p-nitrobenzaldehyde. Moreover, kinetic data of BSA-catalysed aldol condensation of cyclohexanone and p-nitrobenzaldehyde suggest an ordered bi bi mechanism for enone formation; an enamine mechanism involving residues of the catalytic cavity exhibiting abnormal pKa values is also proposed.
- Ardanaz, Sebastián M.,Borucki, Estefanía L.,Velez Rueda, Ana J.,Parisi, Gustavo,Iribarren, Adolfo M.,Iglesias, Luis E.
-
-
- A Ferrocene-Based NH-Free Phosphine-Oxazoline Ligand for Iridium-Catalyzed Asymmetric Hydrogenation of Ketones
-
A new type of ferrocene-based phosphine-oxazoline ligand has been prepared over a few simple steps. An iridium complex of this ligand is air stable and exhibits excellent performance for the asymmetric hydrogenation of simple ketones (up to 98% yield, up to 99% ee, and 20?000 S/C). Exo-α,β-unsaturated cyclic ketones could be regiospecifically hydrogenated to give chiral allylic alcohols with good results. This study indicates that P,N-ligands can also efficiently promote Ir-catalyzed asymmetric hydrogenation without NH-hydrogen-bonding assistance.
- Wang, Yanzhao,Yang, Guoqiang,Xie, Fang,Zhang, Wanbin
-
supporting information
p. 6135 - 6139
(2018/09/27)
-
- Synthesis and cytotoxicity evaluation of novel asymmetrical mono-carbonyl analogs of curcumin (AMACs) against vero, HeLa, and MCF7 cell lines
-
A series of novel asymmetrical mono-carbonyl analogs of curcumin (AMACs) were synthesized and evaluated for cytotoxic activity using BSLT and MTT assay against Vero, HeLa, and MCF7 cell lines. The structures of the synthesized compounds were confirmed by FTIR,1H-NMR,13C-NMR, and mass spectral data. The results of the cytotoxicity evaluation showed that the synthesized compounds exhibited moderate to very high toxic activity in BSLT (LC50 value 29.80–1704.23 μM); most of the compound exhibited cytotoxic activity against HeLa cell lines, which is comparable to the activity of cisplatin (IC50 value 40.65–95.55 μM), and most of the compound tested against MCF7 cell lines exhibited moderate to very high cytotoxic activity (IC50 value 7.86–35.88 μM). However, the selectivity index (SI) of the compounds was low (1–1.96). Among the synthesized compounds, compound 1b was the most cytotoxic and selective against MCF7 cell lines. It could be considered for further development to obtain the more active and selective chemotherapeutic agents against breast cancer.
- Prasetyaningrum, Pekik Wiji,Bahtiar, Anton,Hayun, Hayun
-
-
- Synthesis of symmetrical and unsymmetrical triarylpyrylium ions: Via an inverse electron demand Diels-Alder reaction
-
BF3·OEt2 mediated inverse electron demand Diels-Alder (IEDDA) reaction of chalcones with aryl acetylenes is reported for the synthesis of symmetrical and unsymmetrical 2,4,6-triarylpyrylium ions. The protocol provides an effective one-pot method for the utilization of readily available simple substrates under mild reaction conditions leading to a diverse array of pyrylium ions in moderately good yield.
- Fathimath Salfeena,Basavaraja,Ashitha,Kumar, V. Praveen,Varughese, Sunil,Suresh, Cherumuttathu H.,Sasidhar
-
supporting information
p. 12463 - 12466
(2018/11/20)
-
- Acid/Base-Co-catalyzed Direct Oxidative α-Amination of Cyclic Ketones: Using Molecular Oxygen as the Oxidant
-
A novel acid/base-co-catalyzed direct intermolecular α-amination of various cyclic ketones has been developed for the first time. The reaction employs molecular oxygen as the sole oxidant under metal-free conditions. The reaction tolerates a wide range of various anilines, especially primary diamine derivatives, and provides a simple and efficient method for the constructions of α-amino enones and benzodiazepine derivatives in a single step. (Figure presented.).
- Li, Yi-Jin,Zhang, Lu,Yan, Na,Meng, Xiang-He,Zhao, Yu-Long
-
supporting information
p. 455 - 461
(2017/12/04)
-
- Tuning the Reactivity of Functionalized Diallylic Alcohols: Br?nsted versus Lewis Acid Catalysis
-
The chemodivergent reactivity of bifunctional, enol thioether-containing diallylic alcohols in acidic medium is disclosed, highlighting the difference between strong Lewis acid and mild Br?nsted acid catalysis. In the presence of bismuth(III) triflate, allylic alcohol activation affords diversely substituted cyclopentenones in a Nazarov-type electrocyclization, whereas activation of the thioenol ether by p-toluenesulfonic acid provides an entry to α-sulfenylated β,γ-unsaturated ketones. Both methods represent a facile access to the corresponding products under mild conditions, using inexpensive and non-toxic catalytic systems.
- Lempenauer, Luisa,Du?ach, Elisabet,Lemière, Gilles
-
supporting information
p. 10285 - 10288
(2017/08/07)
-
- BF3·Et2O mediated one-step synthesis of N-substituted-1,2-dihydropyridines, indenopyridines and 5,6-dihydroisoquinolines
-
A simple and efficient one-pot synthesis of N-substituted-1,2-dihydropyridines, indenopyridines and 5,6-dihydroisoquinolines by a BF3·Et2O mediated novel methodology, from easily available α,β-unsaturated ketones/arylidene ketones, phenyl acetylenes and substituted nitriles, has been described. This novel annulation provides quick access to complex polycyclic frameworks with an excellent substrate scope.
- Fathimath Salfeena,Ashitha,Sasidhar
-
supporting information
p. 10165 - 10169
(2016/11/17)
-
- Phosphoric acid mediated tautomerism of imines: Addition of a secondary enamine intermediate to aldehydes
-
A phosphoric acid derivative has been shown to promote the addition between an imine and several aldehyde substrates through an enamine intermediate to give cross-aldol condensation products. The reaction scope and preliminary mechanistic investigations will be presented.
- Davis, Lindsey O.,Putri, Marcella A.,Meyer, Caitlin L.,Durant, Christopher P.
-
p. 3100 - 3103
(2014/05/20)
-
- Fe3O4 nanoparticles as an efficient and magnetically recoverable catalyst for the synthesis of α β-unsaturated heterocyclic and cyclic ketones under solvent-free conditions
-
An efficient and green procedure has been developed for the synthesis of monoarylidenes of cyclic and heterocyclic ketones. The reaction was carried out under solvent-free conditions in the presence of a catalytic amount of nanosized magnetite (Fe3O4). The catalyst was easily removed by using an external magnet. The structures of the products were deduced from their 1H NMR, 13C NMR, and infrared spectroscopy and mass spectrometry. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
- Alishiri, Tooba,Oskooei, Hossein A.,Heravi, Majid M.
-
p. 3357 - 3362
(2013/10/01)
-
- Mixed Cu(ii)-Bi(iii) metal organic framework with a 2D inorganic subnetwork and its catalytic activity
-
The very dense (d = 4.359 g cm-3) three dimensional (3D) hybrid heterometallic framework Bi3O2Cu(OH)(pdc)2 (pdc3-:3,5-pyrazoledicarboxylate), 1, features a 2D inorganic subnetwork representing an unprecedented topological type, and is an effective catalyst for the diastereoselective synthesis of E-α,β-unsaturated ketones.
- Shi, Fa-Nian,Silva, Ana Rosa,Yang, Ting-Hai,Rocha, Joao
-
p. 3776 - 3779
(2013/06/05)
-
- Enantioselective route to ketones and lactones from exocyclic allylic alcohols via metal and enzyme catalysis
-
A general and efficient route for the synthesis of enantiomerically pure α-substituted ketones and the corresponding lactones has been developed. Ruthenium- and enzyme-catalyzed dynamic kinetic resolution (DKR) with a subsequent Cu-catalyzed α-allylic substitution are the key steps of the route. The α-substituted ketones were obtained in high yields and with excellent enantiomeric excess. The methodology was applied to the synthesis of a naturally occurring caprolactone, (R)-10-methyl-6-undecanolide, via a subsequent Baeyer-Villiger oxidation.
- Warner, Madeleine C.,Nagendiran, Anuja,Bogár, Krisztián,B?ckvall, Jan-E.
-
supporting information
p. 5094 - 5097
(2013/01/15)
-
- Aldol condensations of aldehydes and ketones catalyzed by primary amine on water
-
Potassium glycinate-catalyzed aldol condensation reactions of aromatic aldehydes and ketones on water at room temperature have been developed. Under optimal conditions, various condensation adducts are furnished in up to 63 % yield. By simple separation of the oil phase, potassium glycinate-containing water is reused to catalyze aldol condensation for six runs without loss of catalytic activity. Theoretical investigation reveals correlation between the yields and dehydroxylation energy barriers of aldol products, reasonably low activation energy of 11.9 kcal/mol for transition state formation in condensation of benzaldehyde and acetone, vibrations between aldol donor and acceptor, which correspond to the only imaginary frequency (-179.8i).
- Zhang, Xu,Xiong, Yan,Zhang, Shuting,Ling, Xuege,Wang, Jinyue,Chen, Changguo
-
experimental part
p. 751 - 755
(2012/07/28)
-
- Effect of butterfly-shaped sulfur-bridged ligand and counter anions on the catalytic activity and diastereoselectivity of organobismuth complexes
-
In the direct Mannich reaction and synthesis of α,β-unsaturated ketones, the use of organobismuth complexes as catalysts leads to high diastereoselectivity and products of single trans conformation. In this paper, we illustrate the relationship between structure and catalytic activity as well as diastereoselectivity of organobismuth complexes having a 5,6,7,12- tetrahydrodibenz [c,f][1,5]thiobismocine framework as well as bearing a butterfly-shaped sulfur-bridged ligand and tunable anions. With the exposed bismuth center acting as a Lewis acid site and the uncoordinated lone pair electrons of sulfur as a Lewis base site, the cationic organobismuth complexes work as bifunctional Lewis acid/base catalysts. Due to the steric influence of the butterfly-shaped structure and synergistic effect of Lewis acid and Lewis base centers, the complexes can direct substrate attack in organic synthesis. By adjusting the electron-withdrawing ability of the counter anions, the S-Bi bond strength can be regulated, leading to a significant change in Lewis acidity and Lewis basicity as well as catalytic activity. Through synergistic modulation of the above effects, one can control the diastereoselectivity of the organobismuth complexes for the generation of a single diastereoisomer.
- Qiu, Renhua,Yin, Shuangfeng,Song, Xingxing,Meng, Zhengong,Qiu, Yimiao,Tan, Nianyuan,Xu, Xinhua,Luo, Shenglian,Dai, Feng-Rong,Au, Chak-Tong,Wong, Wai-Yeung
-
experimental part
p. 9482 - 9489
(2011/11/13)
-
- Facile separation catalyst system: Direct diastereoselective synthesis of (E)-α,β-unsaturated ketones catalyzed by an air-stable Lewis acidic/basic bifunctional organobismuth complex in ionic liquids
-
The catalyst system that comprises an air-stable bifunctional Lewis acidic/basic organobismuth complex and [Bmim]BF4 is highly efficient in the cross-condensation of aldehydes with ketones. Through switching the reaction from homogeneous to heterogeneous, the system shows facile separation ability and facile reusability.
- Qiu, Renhua,Qiu, Yimiao,Yin, Shuangfeng,Song, Xingxing,Meng, Zhengong,Xu, Xinhua,Zhang, Xiaowen,Luo, Shenglian,Au, Chak-Tong,Wong, Wai-Yeung
-
supporting information; scheme or table
p. 1767 - 1771
(2011/02/23)
-
- Highly efficient and selective synthesis of (E)-α,β-unsaturated ketones by crossed condensation of ketones and aldehydes catalyzed by an air-stable cationic organobismuth perfluorooctanesulfonate
-
An air-stable cationic organobismuth perfluorooctanesulfonate possessing both acidic and basic characters was synthesized, and showed high catalytic activity, diastereoselectivity, stability, and reusability in the one-pot synthesis of (E)-α,β-unsaturated ketones through highly selective crossed condensation of ketones and aldehydes in water.
- Qiu, Renhua,Qiu, Yimiao,Yin, Shuangfeng,Xu, Xinhua,Luo, Shenglian,Au, Chak-Tong,Wong, Wai-Yeung,Shimada, Shigeru
-
experimental part
p. 153 - 162
(2010/06/19)
-
- Highly Enantioselective Hydrogenation of α-Arylmethylene Cycloalkanones Catalyzed by Iridium Complexes of Chiral Spiro Aminophosphine Ligands
-
The highly efficient asymmetric hydrogenation of α-arylmethylene cycloalkanones catalyzed by Ir-complexes of chiral spiro aminophosphine ligands was developed, providing chiral exo-cyclic allylic alcohols at high yields with excellent enantioselectivities (up to 97% ee) and high turnover numbers (S/C up to 10,000). This new reaction provided an efficient method for the synthesis of the key intermediate of the active form of the anti-inflammatory loxoprofen.
- Xie, Jian-Bo,Xie, Jian-Hua,Liu, Xiao-Yan,Kong, Wei-Ling,Li, Shen,Zhou, Qi-Lin
-
supporting information; experimental part
p. 4538 - 4539
(2010/06/17)
-
- Synthesis of hydrogenated indazole derivatives starting with α,β-unsaturated ketones and hydrazine derivatives
-
The reaction of hydrazine derivatives with α,β-unsaturated ketones, such as cyclohexenyl(phenyl)methanone and (E)-2-benzylidenecyclohexanone, were investigated. The reaction between methylhydrazine and e.g., cyclohexenyl(phenyl)methanone was particularly interesting as 3a,4,5,6,7,7a-hexahydro-1-methyl-3-phenyl-1H-indazole was obtained as the major product together with 4,5,6,7-tetrahydro-2-methyl-3-phenyl-2H-indazole as a minor product.
- Nakhai, Azadeh,Bergman, Jan
-
experimental part
p. 2298 - 2306
(2009/07/11)
-
- The palladium-catalyzed aerobic kinetic resolution of secondary alcohols: Reaction development, scope, and applications
-
The first palladium-catalyzed enantioselective oxidation of secondary alcohols has been developed, utilizing the readily available diamine (-)-sparteine as a chiral ligand and molecular oxygen as the stoichiometric oxidant. Mechanistic insights regarding the role of the base and hydrogen-bond donors have resulted in several improvements to the original system. Namely, addition of cesium carbonate and tert-butyl alcohol greatly enhances reaction rates, promoting rapid resolutions. The use of chloroform as solvent allows the use of ambient air as the terminal oxidant at 23°C, resulting in enhanced catalyst selectivity. These improved reaction conditions have permitted the successful kinetic resolution of benzylic, allylic, and cyclopropyl secondary alcohols to high enantiomeric excess with good-toexcellent selectivity factors. This catalyst system has also been applied to the desymmetrization of meso-diols, providing high yields of enantioenriched hydroxyketones.
- Ebner, David C.,Bagdanoff, Jeffrey T.,Ferreira, Eric M.,McFadden, Ryan M.,Caspi, Daniel D.,Trend, Raissa M.,Stoltz, Brian M.
-
supporting information; experimental part
p. 12978 - 12992
(2010/06/19)
-
- Highly enantioselective synthesis of optically active ketones by iridium-catalyzed asymmetric hydrogenation
-
(Chemical Equation Presented) Close to perfect enantioselectivity (up to 99% ee, see scheme) is found for the formation of α-substituted ketones by the asymmetric hydrogenation of enones with an iridium-phosphinooxazoline catalyst. In an operationally simple process, both linear and cyclic substrates react well and afford the desired products in high yields. A wide variety of substituents are tolerated, thus making the method synthetically appealing.
- Lu, Sheng-Mei,Bolm, Carsten
-
supporting information; experimental part
p. 8920 - 8923
(2009/05/30)
-
- Facile formation of bis(3-indolyl)methylarenes by iodine-catalyzed reaction of indole with α,α′-bis(arylmethylene)ketones and α-substituted arylmethyleneketones in dry ethanol
-
Bis(3-indolyl)methylarenes are obtained in good yield by reaction of indole with α,α′-bis(arylmethylene)ketones and α-substituted arylmethyleneketones in dry ethanol using catalytic amount of molecular iodine at room temperature. A plausible mechanism for formation of these products has been suggested.
- Mallik, Asok K.,Pal, Rammohan,Mandal, Tapas K.
-
p. 2056 - 2059
(2008/09/19)
-
- METHOD FOR PRODUCING 2-BENZYLPHENOL COMPOUND
-
[Task] Provide a process for producing a 2-benzylphenol compound easily, efficiently and selectively. [Means for Achievement] A process for producing a 2-benzylphenol compound represented by the following general formula (2) (in the formula, R1, R2, R3 and R4 may be the same or different and are each independently hydrogen atom, alkyl group or the like; and R5, R6, R7, R8 and R9 may be the same or different and are each independently hydrogen atom, alkyl group or the like), characterized by reacting, in the presence of a dehydrogenating agent, a benzylidenecyclohexanone compound represented by the following general formula (1) (in the formula, R1, R2, R3, R4, R5, R6, R7, R8 and R9 have the same definitions as given above). [Effect] A 2-benzylphenol compound substantially free from isomers can be produced from a benzylidenecyclohexanone compound (an easily obtainable raw material) selectively, efficiently and in a simple operation, under mild conditions without using any special reactor.
- -
-
-
- Lithium naphthalenide induced reductive selenenylation of α-cyano ketones: A regiocontrolled process for α-phenylseleno ketones and one-pot conversion into enone system
-
An efficient procedure for the regiocontrolled synthesis of α-phenylseleno ketones has been developed, making use of the lithium naphthalenide induced reductive selenenylation of the α-cyano ketone system as a key operation. Moreover, seleno ketones thus generated in situ, upon subsequent treatment with hydrogen peroxide and acetic acid, could be further converted into the corresponding enones with a high degree of regioselectivity, presumably due to the lithium salt mediated selenoxide syn-elimination process. Georg Thieme Verlag Stuttgart.
- Zhu, Jia-Liang,Ko, Yen-Chun,Kuo, Chun-Wei,Shia, Kak-Shan
-
p. 1274 - 1278
(2008/01/08)
-
- Acid-base catalyses by dimeric disilicoicosatungstates and divacant γ-Keggin-type silicodecatungstate parent: Reactivity of the polyoxometalate compounds controlled by step-by-step protonation of lacunary W{double bond, long}O sites
-
The catalytic properties of disilicoicosatungstates, [{γ-SiW10O32(H2O)2}2(μ-O)2]4- (2) and [H(γ-SiW10O32)2(μ-O)4]7- (3), and their parent divacant γ-Keggin type silicodecatungstate, [γ-SiW10O34(H2O)2]4- (1), toward C-C bond formation reactions have been investigated. The disilicoicosatungstate 2 with aquo ligands exhibits the acidic nature and catalyzes the Mukaiyama-aldol condensation and carbonyl-ene reaction, while 1 and 3 are rather basic and catalyze the Knoevenagel condensation. Therefore, the acid-base properties of a series of lacunary γ-Keggin silicotungstate derivatives 1-3 are clearly different, and the catalyses of 1-3 depend on the molecular structures while 1-3 are composed of a common [SiW10O32] fragment.
- Yoshida, Akihiro,Hikichi, Shiro,Mizuno, Noritaka
-
p. 455 - 459
(2008/02/06)
-
- Remarkably chemoselective reduction of unmodified Baylis-Hillman adducts by InCl3/NaBH4: Application to the stereoselective synthesis of trisubstituted alkenones including two alarm pheromones
-
A novel, convenient and solely stereoselective synthesis of trisubstituted E-alkenones has been achieved by InCl3/NaBH4 mediated chemoselective reduction of unmodified Baylis-Hillman adducts derived from vinyl ketones and cycloalkenones for the first time. The efficiency of this methodology in the practical synthesis of (S)-(+)-manicone and (S)-(+)-normanicone, two alarm pheromones of Manica ants, has been demonstrated. Georg Thieme Verlag Stuttgart.
- Das, Biswanath,Banerjee, Joydeep,Chowdhury, Nikhil,Majhi, Anjoy,Holla, Harish
-
p. 1879 - 1882
(2008/02/08)
-
- Ring expansion/homologation-aldehyde condensation cascade using tert-trihalomethylcarbinols
-
Treatment of cyclic tert-trihalomethylcarbinols with CrCl2 in THF/HMPA in the presence of aryl or aliphatic aldehydes initiates a cascade sequence of one carbon ring expansion-olefination affording conjugated exocyclic ketones. Acyclic tert-trihalomethylcarbinols undergo a comparable cascade of one carbon homologation-olefination.
- Falck,He, Anyu,Manmohan Reddy,Kundu, Abhijit,Barma, Deb K.,Bandyopadhyay,Kamila, Sukanta,Akella, Radha,Bejot, Romain,Mioskowski, Charles
-
p. 4645 - 4647
(2007/10/03)
-
- Reactions of 2,6-dibenzylidenecyclohexanone and its derivatives in high-temperature water
-
The reactivity of derivatives of 2,6-dibenzylidenecyclohexanone was investigated in water at 220?250°C under microwave conditions, without added catalyst. Retro-Claisen?Schmidt processes predominated. Hydrolytic attack at the benzylic position afforded a 2-benzylidenecyclohexanone derivative and liberated an aryl aldehyde. Dienones substituted with electron-withdrawing or -donating groups on the aryl rings were more susceptible to hydrolysis than was the parent 2,6-dibenzylidenecyclohexanone. CSIRO 2006.
- Bi, Xian-Jun,Higham, Luke T.,Scott, Janet L.,Strauss, Christopher R.
-
p. 883 - 886
(2008/02/11)
-
- Aldol condensation in water using polyethylene glycol 400
-
Efficient and environmentally friendly synthesis of chalcones and 2,6-bis(arylmethylidene)cycloalkanones was carried out by aldol condensation of ketones with aromatic aldehydes in water in the presence of polyethylene glycol 400. Copyright
- Tanemura, Kiyoshi,Suzuki, Tsuneo,Nishida, Yoko,Horaguchi, Takaaki
-
p. 576 - 577
(2007/10/03)
-
- A new protocol for synthesis of α,β-unsaturated ketones using zirconium tetrachloride under microwave irradiation
-
A facile one-pot synthesis of α,β-unsaturated carbonyl compound has been accomplished from ZrCl4 mediated condensation of α-bromo ketones with aryl aldehydes under microwave irradiation.
- Bora, Utpal,Saikia, Anil,Boruah, Romesh C.
-
p. 2523 - 2526
(2007/10/03)
-
- Selective synthesis of α,β-unsaturated ketones by dibutyltin dimethoxide-catalyzed condensation of aldehydes with alkenyl trichloroacetates
-
(Chemical Equation Presented) Various α,β-unsaturated ketones were stereoselectively synthesized in high yields up to 94% by a condensation reaction between alkenyl trichloroacetates and aldehydes using dibutyltin dimethoxide as a catalyst in the presence of methanol. This process is superior to the classical Claisen-Schmidt condensation with respect to mildness of the base catalyst and product selectivity.
- Yanagisawa, Akira,Goudu, Riku,Arai, Takayoshi
-
p. 4281 - 4283
(2007/10/03)
-
- Rhodium-catalyzed intramolecular hydroacylation of 5- and 6-alkynals: Convenient synthesis of α-alkylidenecycloalkanones and cycloalkenones
-
A novel intramolecular hydroacylation of 5- and 6-alkynals leading to α-alkylidenecycloalkanones was accomplished by using cationic a rhodium(I)/BINAP complex. For all cyclizations described, a single (E)-olefin isomer was obtained. At elevated temperature, hydroacylation and double bond migration of 5- and 6-alkynals proceeded in a one-pot reaction to give cycloalkenones. An intramolecular hydroacylation of a 7-alkynal was unsuccessful. This method represents an attractive new route to highly functionalized α-alkylidenecycloalkanones and cycloalkenones.
- Takeishi, Kenzo,Sugishima, Koudai,Sasaki, Kaori,Tanaka, Ken
-
p. 5681 - 5688
(2007/10/03)
-
- Direct preparation of monoarylidene derivatives of aldehydes and enolizable ketones with DIMCARB
-
(Matrix presented) Aryl α,β-unsaturated ketones and aldehydes were synthesized, in moderate to excellent yields, with use of dimethylammonium dimethyl carbamate (DIMCARB) as a recyclable reaction medium and as a catalyst.
- Kreher, Ulf P.,Rosamilia, Anthony E.,Raston, Colin L.,Scott, Janet L.,Strauss, Christopher R.
-
p. 3107 - 3110
(2007/10/03)
-
- 5-Amino-1-pentene-3-ol substituted derivatives
-
The invention relates to 5-amino-1-pentene-3-ol substituted derivatives, a method for the production thereof, medicaments containing said compounds, the use of substituted 5-amino-1-pentene-3-ol derivatives for the production of medicaments, and methods of treatment using the medicaments.
- -
-
-
- Rhodium(I)-catalyzed acylation of alkyne with acylsilane: Transformation of 5- or 6-alkynoylsilane to α-alkylidenecycloalkanone
-
Rhodium(I)-catalyzed intramolecular acylation of alkynyl group proceeds by the use of acylsilanes having an alkynyl moiety. 5-and 6-Alkynoylsilanes are converted to α-alkylidenecycloalkanones by treatment with [RhCl(CO)2]2 in the presence of acetic acid via transmetallation between the acylsilane moiety and a rhodium(I) complex.
- Yamane, Motoki,Amemiya, Takuma,Narasaka, Koichi
-
p. 1210 - 1211
(2007/10/03)
-
- The reaction of enaminones with grignard reagents: Synthesis of α,β- unsaturated ketones
-
Enaminones in toluene react with Grignard reagents in tetrahydrofuran at 0-25 °C, to give selectively and with high yields the corresponding α,β- unsaturated ketones.
- Fontenas,Ait-Haddou,Bejan,Balavoine
-
p. 1743 - 1753
(2007/10/03)
-
- Applications of the β-azidonation reaction to organic synthesis. α,β- Enones, conjugate addition, and γ-lactam annulation
-
The β-azido functionalization reaction provides a mechanistically different enone synthesis that involves treatment of 2 with fluoride anion to effect desilylation and concomitant β-elimination to give 3. Table 1 lists a number of examples of the direct conversion of a TIPS enol ether into the corresponding α,β-enone via a β-azido TIPS enol ether. The β-azido group can be ionized with Me3Al or Me2AlCl and the intermediate enonium ion trapped by a variety of nucleophiles such as an allylstannane, electron-rich aromatics, TMS enol ethers, Et2AlCN, Me2AlCCR, Me4AlLi, and vinylaluminum reagents to give the products listed in Table 2. The diastereoselectivity of the reaction of a 4-substituted enonium ion with indole shows an unusual increase of selectivity with increasing temperature. Reduction of the azide 2 provides access to β-amino TIPS enol ethers 5, which, for example, can be converted into a cinnamide derivative and cyclized via a putative 'ene' process into a γ-lactam.
- Magnus, Philip
-
p. 12486 - 12499
(2007/10/03)
-
- Chemoselective and stereoselective debromination of vicinal-dibromides with sodium dithionite
-
A simple and efficient procedure for the quantitative debromination of vic-dibromides has been reported with sodium dithionite at ambient temperature. These eliminations are chemoselective and also stereoselective.
- Khurana, Jitender M.,Sehgal, Arti
-
p. 3791 - 3798
(2007/10/03)
-
- Reactions of tin(IV) enolates obtained from O-stannyl ketyls under neutral free radical conditions
-
Under mild and neutral free radical conditions, an α,β-unsaturated ketone reacted with tributyltin hydride to produce an intermediate resonance-stabilized allylic O-stannyl ketyl. Upon subsequent hydrogen atom abstraction, a tin(IV) enolate was afforded which could be quenched with a variety of electrophiles and form new carbon-carbon bonds. Aldehydes react to produce aldol-type products and both intramolecular and intermolecular carbonyl addition reactions were investigated using this strategy. Using similar methodology, the tin(IV) enolate could be quenched in the presence of HMPA with various alkyl halides and α,β-unsaturated carbonyl compounds (Michael acceptors) to yield alkylated products in good yields. These reactions represent a very mild regioselective alternative to metal enolate formation which usually requires strong bases such as LDA or strongly reductive dissolving metal conditions to achieve success. New carbon skeletons for natural product synthesis can be readily constructed using this chemically neutral approach.
- Enholm, Eric J.,Whitley, Paul E.,Xie, Yongping
-
p. 5384 - 5390
(2007/10/03)
-