- Nickel-Catalyzed Alkyl-Alkyl Cross-Electrophile Coupling Reaction of 1,3-Dimesylates for the Synthesis of Alkylcyclopropanes
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Cross-electrophile coupling reactions of two Csp3-X bonds remain challenging. Herein we report an intramolecular nickel-catalyzed cross-electrophile coupling reaction of 1,3-diol derivatives. Notably, this transformation is utilized to synthesize a range of mono- and 1,2-disubstituted alkylcyclopropanes, including those derived from terpenes, steroids, and aldol products. Additionally, enantioenriched cyclopropanes are synthesized from the products of proline-catalyzed and Evans aldol reactions. A procedure for direct transformation of 1,3-diols to cyclopropanes is also described. Calculations and experimental data are consistent with a nickel-catalyzed mechanism that begins with stereoablative oxidative addition at the secondary center.
- Chen, Pan-Pan,Hong, Xin,Jarvo, Elizabeth R.,McGinnis, Tristan M.,Sanford, Amberly B.,Thane, Taylor A.
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supporting information
(2020/03/23)
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- Lewis Base-Promoted Ring-Opening 1,3-Dioxygenation of Unactivated Cyclopropanes Using a Hypervalent Iodine Reagent
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A facile and effective system has been developed for the regio- and chemoselective ring-opening/electrophilic functionalization of cyclopropanes through C?C bond activation by [bis(trifluoroacetoxy)iodo]benzene with the aid of the Lewis basic promoter p-toluenesulfonamide. The p-toluenesulfonamide-promoted system works well for a wide range of cyclopropanes, resulting in the formation of 1,3-diol products in good yields and regioselectivity.
- Gieuw, Matthew H.,Ke, Zhihai,Yeung, Ying-Yeung
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supporting information
p. 3782 - 3786
(2018/03/13)
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- Synthesis of novel chiral TBBt derivatives with hydroxyl moiety. Studies on inhibition of human protein kinase CK2α and cytotoxicity properties
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The efficient method for the synthesis of novel 4,5,6,7-tetrabromo-1H- benzotriazole (TBBt) derivatives bearing a single stereogenic center has been developed. New compounds with a variety of substituents at the meta- and para-position of the phenyl ring are reported. All of the presented compounds were obtained using classical synthetic methods, such as bromination of benzotriazole, and its subsequent alkylation by monotosylated arylpropane-1,3-diols, which in turn have been synthesized through reduction of the corresponding prochiral β-keto esters, and the selective monotosylation of the primary hydroxyl group. The influence of the new and previously reported N-hydroxyalkyl TBBt derivatives on the activity of human protein kinase CK2α catalytic subunit was examined. The most active were derivatives with N-hydroxyalkyl substituents (IC50 in 0.80-7.35 μM range). A binding mode of (R)-1-(4,5,6,7-tetrabromo-2H-benzotriazol-2-yl)butan-3-ol 7b to hCK2α has been proposed based on in silico docking studies. Additionally, MTT-based cytotoxicity tests demonstrated high activities of novel 1-aryl-3-TBBt-propan-1-ol and 3-TBBt-propan-1,2-diol derivatives against human peripheral blood T lymphoblast (CCRF-CEM), and moderate anti-tumor activities against human breast adenocarcinoma (MCF7) cell lines.
- Borowiecki, Pawe?,Wawro, Adam M.,Wińska, Patrycja,Wielechowska, Monika,Bretner, Maria
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supporting information
p. 364 - 374
(2014/08/05)
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- Studies on the chemoenzymatic synthesis of (R)- and (S)-methyl 3-aryl-3-hydroxypropionates: The influence of toluene-pretreatment of lipase preparations on enantioselective transesterifications
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Two series (para- and meta-substituted) of racemic methyl esters of 3-aryl-3-hydroxypropionic acid were prepared after which the enantiomers were separated by an enzyme-catalyzed transesterification. Several lipases were investigated as the catalyst. The influence of the enzyme pretreatment, as well as substrate concentration, reaction temperature, stirring manner, and substrate conversion on the stereochemical outcome of the biotransformation process were investigated in detail. The best results were achieved by using solvent-pretreated lipase from Pseudomonas fluorescens or Burkholderia cepacia suspended in toluene, and vinyl acetate as the acetyl group donor.
- Borowiecki, Pawel,Bretner, Maria
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p. 925 - 936
(2013/09/23)
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- Tandem catalysis by lipase in a vinyl acetate-mediated cross-aldol reaction
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The lipase Novozym435 (0.6% w/w) was used in tandem with organocatalysts in a first vinyl/isopropenyl acetate-mediated aldol reaction. The reaction was facilitated through the lipase-catalyzed in situ generation of acetaldehyde/acetone. The important features of the present methodology include the mild and facile reaction conditions, regenerability of the lipase, comparatively high yields and minimal side product formation.
- Kumar, Manjeet,Shah, Bhahwal A.,Taneja, Subhash C.
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p. 1207 - 1212
(2011/06/25)
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- Synthesis and characterization of a novel liver-targeted prodrug of cytosine-1-β-D-arabinofuranoside monophosphate for the treatment of hepatocellular carcinoma
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Cytotoxic nucleosides have proven to be ineffective for the treatment of hepatocellular carcinoma (HCC) due, in part, to their inadequate conversion to their active nucleoside triphosphates (NTP) in the liver tumor and high conversion in other tissues. Th
- Boyer, Serge H.,Sun, Zhili,Jiang, Hongjian,Esterbrook, Julie,Gómez-Galeno, Jorge E.,Craigo, William,Reddy, K. Raja,Ugarkar, Bheemarao G.,MacKenna, Deidre A.,Erion, Mark D.
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p. 7711 - 7720
(2007/10/03)
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- Synthesis of benzanilide derivatives as dual acting agents with α1- adrenoceptor antagonistic action and steroid 5-α reductase inhibitory activity
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Synthesis of benzanilide derivatives which have dual α1-adrenoceptor antagonistic action and steroid 5α-reductase inhibitory activity and their structure-activity relationships is described.
- Yoshida, Kiyoshi,Horikoshi, Yoichiro,Eta, Masaaki,Chikazawa, Jun,Ogishima, Masayuki,Fukuda, Yohichi,Sato, Hiroki
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p. 2967 - 2972
(2007/10/03)
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