- Heck-Type Arylation of 2-Cycloalken-1-ones with Arylpalladium Intermediates Formed by Decarboxylative Palladation and by Aryl Iodide Insertion
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(Matrix presented) A palladium-catalyzed decarboxylative arylation reaction was shown to produce Heck-type coupling products using a number of different arene carboxylic acid and 2-cycloalken-1-one substrates. The more conventional Heck coupling of an aryl iodide and a 2-cycloalken-1-one reactant was also briefly explored for comparison, where it was found that phosphine-free (Jeffery) conditions afforded the highest yield of product.
- Tanaka, Daisuke,Myers, Andrew G.
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- Copper-Catalyzed Enantioselective 1,2-Reduction of Cycloalkenones
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We report an asymmetric 1,2-reduction of cyclic α,β-unsaturated ketones to access various enantiomerically enriched cyclic allylic alcohols under mild conditions, catalyzed by in situ generated copper hydride ligated with (R)-DTBM-C3*-TunePhos. α-Brominated cycloalkenones were reduced with excellent enantioselectivities of up to 98% ee, while substrates that were without α-substituents were reduced chemoselectively, with moderate enantioselectivities.
- Shi, Yongjie,Wang, Jingxin,Yin, Qin,Zhang, Xumu,Chiu, Pauline
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supporting information
p. 5658 - 5663
(2021/08/01)
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- Catalytic enantioselective total synthesis of (?)-ar-Tenuifolene
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First catalytic asymmetric total synthesis of aromatic sesquiterpene, (?)-ar-teunifolene (1) is featured (3 steps, 75% overall yields) from commercially available 3-methyl cyclohex-2-enone 16. The enantioenriched 3,3-disubstituted cyclohexanone 11 is obtained from Pd(II)-catalyzed enantioselective (p-tolyl)boronic acid addition to 3-methyl cyclohex-2-enone 16 in 90% ee, which is found to be the key intermediate. A diastereoselective methyllithium addition of this enantioenriched product followed by dehydration completes straightforward access to (?)-ar-teunifolene (1).
- Shaw, Kundan,Niyogi, Sovan,Bisai, Vishnumaya
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supporting information
(2020/03/23)
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- Synthesis of chiral seven-membered β-substituted lactams: Via Rh-catalyzed asymmetric hydrogenation
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Rh/bisphosphine-thiourea ligand (ZhaoPhos)-catalyzed asymmetric hydrogenation of seven-membered β-substituted α,β-unsaturated lactams was successfully developed to prepare various chiral seven-membered β-substituted lactams with good to excellent results (up to >99% conversion, 99% yield, and >99% ee).
- Huang, Yi,Li, Pan,Dong, Xiu-Qin,Zhang, Xumu
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supporting information
p. 8819 - 8823
(2018/11/30)
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- An Electrophilic Trifluoromethylthiolation of Silylenol Ethers and β-Naphthols with Diethylaminosulfur Trifluoride and (Trifluoromethyl)trimethylsilane
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An efficient and general trifluoromethylthiolation of silylenol ethers and β-naphthols have been accomplished employing the combination of diethylaminosulfur trifluoride (DAST) and (trifluoromethyl)trimethylsilane (CF3TMS) as source of electrophilic trifluoromethylthio moiety for the synthesis of α-trifluoromethylthiolated carbonyl compounds and β-naphthols in good yields. Important features of this method include wide functional group tolerance and use of readily available DAST/CF3TMS. Potential of the methodology was demonstrated via the synthesis of α-trifluoromethylthiolated (+)-4-cholesten-3-one and naphthoquinone. (Figure presented.).
- Saravanan, Perumal,Anbarasan, Pazhamalai
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p. 2894 - 2899
(2018/08/17)
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- A highly efficient metal-free approach to: Meta - And multiple-substituted phenols via a simple oxidation of cyclohexenones
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A novel and efficient metal-free approach to substituted phenols has been disclosed from simple and readily available cyclohexenones and cyclohexenone equivalents. Dimethyl sulfoxide (DMSO), a simple and common organic reagent, was employed as a mild oxidant in this I2-catalysis, which significantly tolerates various substituents including some easily oxidizable or reducible functionalities. The challenging meta- and multiple-substituted phenols could be well prepared by this method. The metal-free and mild oxidation make this protocol very simple, practical, and easy to handle.
- Liang, Yu-Feng,Song, Song,Ai, Lingsheng,Li, Xinwei,Jiao, Ning
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supporting information
p. 6462 - 6467
(2018/06/08)
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- Copper/Selectfluor-System-Catalyzed Dehydration-Oxidation of Tertiary Cycloalcohols: Access to β-Substituted Cyclohex-2-enones, 4-Arylcoumarins, and Biaryls
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A route to β-substituted cyclohex-2-enones, 4-arylcoumarins, and biaryls has been developed. This approach involves a one-pot Cu0/Selectfluor-catalyzed dehydration-oxidation of tertiary cycloalcohols. Thus, by using 2 equiv. of Selectfluor at 25 C, the dehydration-oxidation of tertiary cyclohexanols and oxabenzocyclohexanols gave β-substituted cyclohex-2-enones and 4-arylcoumarins, respectively; whereas the dehydration-oxidation of tertiary cyclohexanols gave biaryls as the final products by using 2.5 equiv. of Selectfluor at 80 C. A route to β-substituted cyclohex-2-enones, 4-arylcoumarins, and biaryls has been developed. This approach involves a one-pot Cu0/Selectfluor-catalyzed dehydration-oxidation of tertiary cycloalcohols.
- Ren, Shaobo,Zhang, Jian,Zhang, Jiahui,Wang, Heng,Zhang, Wei,Liu, Yunkui,Liu, Miaochang
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supporting information
p. 5381 - 5388
(2015/08/24)
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- Continuous-Flow Synthesis of meta-Substituted Phenol Derivatives
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Two complementary microreactor technologies were developed for the study of biphasic gas-liquid reactions and preparation of meta-substituted phenol derivatives. The first capillary microreactor, composed of a T-junction and simple capillary, enabled oxidative Heck/dehydrogenation on a microgram scale with a shortened reaction time; the total sequence time for oxidative Heck/dehydrogenation reactions was optimized from 2160 min in a traditional batch system to 130 min in the microchemical system. The second tube-in-tube microreactor, composed of a gas-permeable inner tube and gas-nonpermeable outer tube, successfully performed a gram-scale synthesis under the optimized safety and economic conditions which were established from the first microgram-scale study. The two microreactors have great potential for exploring reactions involving gaseous and liquid reagents.
- Park, Jeong Hyeon,Park, Chan Yi,Kim, Mi Jin,Kim, Min Uk,Kim, Young Joon,Kim, Geon-Hee,Park, Chan Pil
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supporting information
p. 812 - 818
(2015/07/27)
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- Isopropylmagnesium chloride-promoted unilateral addition of Grignard reagents to β-diketones: One-pot syntheses of β-tertiary hydroxyl ketones or 3-substituted cyclic-2-enones
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The regioselective unilateral additions of Grignard reagents to acyclic or cyclic β-diketones were effectively promoted by sub-stoichiometric amounts of i-PrMgCl to afford β-tertiary hydroxyl ketones or 3-substituted cyclic-2-enones, respectively. Also, the addition of Grignard reagents to acyclic β-diketones followed by a reaction with cyclic β-diketones in a one-pot process was put forward. The reaction mechanism was discussed in detail to explain the high regioselectivity via chemical experiments, hydrogen-deuterium exchange and mass spectrometry.
- Yuan, Rui,Zhao, Dan,Zhang, Li-Yuan,Pan, Xiang,Yang, Yan,Wang, Pei,Li, Hong-Feng,Da, Chao-Shan
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supporting information
p. 724 - 728
(2016/01/12)
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- Palladium-catalyzed oxidative rearrangement of tertiary allylic alcohols to enones with oxygen in aqueous solvent
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A one-pot procedure for Pd(TFA)2-catalyzed 1,3-isomerization of tertiary allylic alcohols to secondary allylic alcohols followed by a Pd(TFA)2/neocuproine-catalyzed oxidative reaction to β-disubstituted-α,β-unsaturated kenones was developed. (Chemical Equation Presented).
- Li, Jingjie,Tan, Ceheng,Gong, Jianxian,Yang, Zhen
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supporting information
p. 5370 - 5373
(2015/01/09)
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- Highly enantioselective synthesis of chiral cyclic allylic amines via RH-catalyzed asymmetric hydrogenation
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Highly regioselective and enantioselective asymmetric hydrogenation of cyclic dienamides catalyzed by an Rh-DuanPhos complex has been developed, which provides a readily accessible method for the synthesis of chiral cyclic allylic amines in excellent enantioselectivities (up to 99% ee). The products are valuable chiral building blocks and could be easily transformed to multisubstituted cyclohexane derivatives.
- Zhou, Ming,Liu, Tang-Lin,Cao, Min,Xue, Zejian,Lv, Hui,Zhang, Xumu
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p. 3484 - 3487
(2014/07/21)
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- Aerobic oxidative heck/dehydrogenation reactions of cyclohexenones: Efficient access to meta-substituted phenols
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Jockeying for the (meta)position: A new dicationic palladium(II) catalyst, employing a 6,6′-dimethyl-2,2′-bipyridine ligand, promotes both the aerobic oxidative Heck coupling and dehydrogenation reactions of cyclohexenones. These reactions may be combined in a one-pot sequence to enable the straightforward synthesis of meta-substituted phenols (see scheme). Copyright
- Izawa, Yusuke,Zheng, Changwu,Stahl, Shannon S.
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supporting information
p. 3672 - 3675
(2013/04/23)
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- Pt-catalyzed oxidative rearrangement of cyclic tertiary allylic alcohols to enones using aqueous hydrogen peroxide
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An oxidative rearrangement of cyclic tertiary allylic alcohols to β-disubstituted α,β-unsaturated ketones by Pt black catalyst with aqueous hydrogen peroxide is described. The reaction proceeds under organic solvent- and halide-free conditions and gives only water as a coproduct. The Pt black catalyst is commercially available and can be reused at least four times.
- Nagamine, Takashi,Kon, Yoshihiro,Sato, Kazuhiko
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supporting information; experimental part
p. 744 - 746
(2012/09/22)
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- Pd-diimine: A highly selective catalyst system for the base-free oxidative heck reaction
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Pd(OAc)2/3 is an efficient catalyst system for the base-free oxidative Heck reaction that outperforms the currently available catalysts for the more challenging substrates studied. The catalyst system is highly selective, and works at room temperature with dioxygen as the oxidant.
- Gottumukkala, Aditya L.,Teichert, Johannes F.,Heijnen, Dorus,Eisink, Niek,Van Dijk, Simon,Ferrer, Catalina,Van Den Hoogenband, Adri,Minnaard, Adriaan J.
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supporting information; experimental part
p. 3498 - 3501
(2011/06/22)
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- Palladium-catalyzed Mizoroki-Heck-type reaction of aryl trimethoxysilanes
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A palladium-catalyzed Mizoroki-Heck-type reaction of aryl trimethoxysilanes with olefins is described. A series of ArSi(OMe)3 and olefins, including electron-rich and electron-deficient analogues worked well in the procedure, affording the arylation products in moderate to good yields. Georg Thieme Verlag Stuttgart.
- Ye, Zhishi,Chen, Fan,Luo, Fang,Wang, Wenhui,Lin, Baoda,Jia, Xiaofei,Cheng, Jiang
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supporting information; experimental part
p. 2198 - 2200
(2011/03/19)
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- Synthesis of α,β-unsaturated aryl esters via Heck reaction of unsymmetrical aryl tellurides
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A variety of α,β-unsaturated aryl esters were prepared by the direct reaction of unsymmetrical aryltellurides and ethyl acrylate, catalyzed by PdCl2 via a Heck cross-coupling reaction.
- Stefani, Hélio A.,Pena, Jesus M.,Gueogjian, Kemilla,Petragnani, Nicola,Vaz, Boniek G.,Eberlin, Marcos N.
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scheme or table
p. 5589 - 5595
(2011/02/22)
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- Enantioselective hydrogenation of enones with a hydroformylation catalyst
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Use of a typical rhodium precatalyst for hydroformylation results in the enantioselective hydrogenation of cyclic enones with up to 90% ee. Extensive screening of chiral ligands reveals the simple ligand Chiraphos as the best ligand, so far. The hydrogenation shows high chemoselectivity. Exclusive formation of saturated, chiral b-branched ketones is observed. It is proposed that the catalyst follows a frustrated hydroformylation pathway ("monohydride-based mechanism") and differs by that from the classical cationic Schrock-Osborn type rhodium precatalysts ("dihydride-based mechanism") for enantioselective hydrogenation. The catalyst operates under neat conditions and is easily recyclable by simply distilling off the reaction mixture and treatment with syn gas prior to hydrogenation.
- Scheuermann Nee Taylor, Caroline J.,Jaekel, Christoph
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supporting information; experimental part
p. 2708 - 2714
(2009/10/06)
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- Copper/silver-cocatalyzed conia-ene reaction of linear β-alkynic β-ketoesters
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A novel and general copper/silver catalytic system has been developed for the Conia-ene intramolecular reaction of linear β-alkynic β-ketoesters. In the presence of (CuOTf)2·C 6H6 and AgSbF6 (or AgOAc), a variety of the linear β-alkynic β-ketoesters selectively underwent the Conia-ene intramolecular reaction in moderate to good yields.
- Deng, Chen-Liang,Song, Ren-Jie,Guo, Sheng-Mei,Wang, Zhi-Qiang,Li, Jin-Heng
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p. 5111 - 5114
(2008/03/27)
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- 1-(2-Iodophenyl)-1H-tetrazole as a ligand for Pd(II) catalyzed Heck reaction
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1-(2-Iodophenyl)-1H-tetrazole 2 was synthesized by the reaction of 2-iodoaniline, sodium azide and triethyl orthoformate in acetic acid. The newly synthesized ligand 2 was successfully used in Heck reaction to give the cross-coupled products in excellent yields.
- Gupta, Arun Kumar,Song, Chung Hyun,Oh, Chang Ho
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p. 4113 - 4116
(2007/10/03)
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- Two methods for the preparation of 2-cyclohexenones from resin-bound 1,3-cyclohexanedione
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The addition of organolithium or Grignard reagents to viny]ogous ester resin 1 followed by mild hydrolysis of product resins 2 provides 3-alkyl-2-cyclohexenones in high purity (>95%). Alternatively, conversion of 1 to vinyl triflate resin 4 followed by palladium-mediated couplings with aryl boronic acids and hydrolysis furnishes 3-ary]-2-cyclohexenones in lower yield, but exceptional purity.
- Fraley, Mark E.,Rubino, Robert S.
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p. 3365 - 3368
(2007/10/03)
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- A New Catalytic Activity of Antimony(III) Chloride in Palladium(0)-Catalyzed Conjugate Addition of Aromatics to α,β-Unsaturated Ketones and Aldehydes with Sodium Tetraphenylborate and Arylboronic Acids
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A remarkable catalytic effect of antimony(III) chloride is disclosed in palladium(0)-catalyzed conjugate addition of aromatics to α,β-unsaturated ketones and aldehydes with sodium tetraphenylborate and arylboronic acids in acetic acid at 25 deg C.Several other metal chlorides such as AlCl3, SnCl4, AsCl3, TiCl4, FeCl3, MoCl5, and CeCl3 are also effective in some cases, but SbCl3 is the salt of choice.Two key steps are proposed for this reaction: one is the oxidative addition of a C-B bond to Pd(0) forming an arylpalladium species, and the other is the formation of an antimony enolate derived from the initial coordination of SbCl3 to the carbonyl oxygen of an organopalladium intermediate.
- Cho, Chan Sik,Motofusa, Shin-ichi,Ohe, Kouichi,Uemura, Sakae,Shim, Sang Chul
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p. 883 - 888
(2007/10/02)
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- Synthesis and structure-activity relationships of new ACAT inhibitors
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A series of heterocyclic ureas were synthesized and their ability to inhibit arterial and intestinal ACAT was assessed in animals.The structural modifications carried out in this series led to N2-(2,4-difluorophenyl)-N1-8-(4-fluorophenyl)-2,3,4,5-tetrahydro-1-benzoxepin-5-yl-N1-n-heptylurea 21, which proved to be very active on both the inhibition of aortic ACAT and the inhibition of rat cholesterol intestinal absorption, thus exhibiting a strong hypocholesterolemic effect po in rat (ED25 = 0.2 mg/kg). aortic ACAT / intestinal inhibition / benzoxepin / urea / cholesterol / hypocholesterolaemic activity
- Nioche, J. Y.,Decerprit, J.,Festal, D.
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p. 377 - 386
(2007/10/02)
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- New Helical Hydrocarbons, VII. Clamped Quaterphenyl Hydrocarbons
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The new many-membered hydrocarbons 1 - 4 are synthesized starting with 3-ethoxycyclohexenone; 5 is available through Ullmann-coupling.DNMR studies show that these molecular skeletons with the exception of 4 are comparatively rigid helices.The larger sulfi
- Wittek, Mechtild,Voegtle, Fritz
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p. 2533 - 2539
(2007/10/02)
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