872672-13-4Relevant academic research and scientific papers
Cobalt-Catalyzed Diastereo- And Enantioselective Reductive Allyl Additions to Aldehydes with Allylic Alcohol Derivatives via Allyl Radical Intermediates
Wang, Lei,Wang, Lifan,Li, Mingxia,Chong, Qinglei,Meng, Fanke
, p. 12755 - 12765 (2021/08/30)
Catalytic generation of ambiphilic π-allyl-metal complexes and their utility in enantioselective transformations constitutes a powerful approach for introduction of allyl groups to a molecule. Herein an unprecedented cobalt-catalyzed highly site-, diastereo-, and enantioselective protocol for stereoselective formation of nucleophilic allyl-Co(II) complexes followed by addition to aldehydes is presented. The reaction features diastereo- and enantioconvergent conversion of easily accessible allylic alcohol derivatives to diversified enantioenriched homoallylic alcohols with a remarkably broad scope of allyl groups that can be introduced. Mechanistic studies indicated that allyl radical intermediates were involved in this process. These new discoveries establish a new strategy for development of enantioselective transformations through capture of radicals by chiral Co complexes, pushing forward the frontier of Co complexes for enantioselective catalysis.
Ouabain 19-site primary hydroxyl derivative as well as preparation method and application thereof
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Paragraph 0063-0070, (2020/12/05)
The invention provides an ouabain 19-site primary hydroxyl derivative as well as a preparation method and application thereof. The structure of the ouabain 19-site primary hydroxyl derivative is shownas a formula I. The derivative has very low toxicity to normal cells and also has an excellent effect of inhibiting tumor cells. In addition, the derivative can effectively inhibit tumor cell migration and invasion. Therefore, the ouabain 19-site primary hydroxyl derivative has a very good application prospect in preparation of drugs for resisting tumors and inhibiting tumor invasion and/or migration.
Stereodivergent allylic substitutions with aryl acetic acid esters by synergistic iridium and lewis base catalysis
Jiang, Xingyu,Beiger, Jason J.,Hartwig, John F.
supporting information, p. 87 - 90 (2017/05/16)
The preparation of all possible stereoisomers of a given chiral molecule bearing multiple stereocenters by a simple and unified method is a significant challenge in asymmetric catalysis. We report stereodivergent allylic substitutions with aryl acetic acid esters catalyzed synergistically by a metallacyclic iridium complex and benzotetramisole. Through permutations of the enantiomers of the two chiral catalysts, all four stereoisomers of the products bearing two adjacent stereocenters are accessible with high diastereoselectivity and enantioselectivity. The resulting chiral activated ester products can be converted readily to enantioenriched amides, unactivated esters, and carboxylic acids in a onepot manner.
Asymmetric Dearomatization/Cyclization Enables Access to Polycyclic Chemotypes
Hayashi, Mikayo,Brown, Lauren E.,Porco, John A.
, p. 4800 - 4804 (2016/10/13)
Enantioenriched, polycyclic compounds were obtained from a simple acylphloroglucinol scaffold. Highly enantioselective dearomatization was accomplished using a Trost ligand–palladium(0) complex. A computational DFT model was developed to rationalize observed enantioselectivities and revealed a key reactant-ligand hydrogen bonding interaction. Dearomatized products were used in visible light-mediated photocycloadditions and oxidative free radical cyclizations to obtain novel polycyclic chemotypes including tricyclo[4.3.1.01,4]decan-10-ones, bicyclo[3.2.1]octan-8-ones and highly substituted cycloheptanones.
Catalytic Asymmetric Umpolung Allylation of Imines
Liu, Jie,Cao, Chao-Guo,Sun, Hong-Bao,Zhang, Xia,Niu, Dawen
supporting information, p. 13103 - 13106 (2016/10/22)
Here we report an iridium-catalyzed asymmetric umpolung allylation of imines as a general approach to prepare 1,4-disubstituted homoallylic amines, a fundamental class of compounds that are hitherto not straightforward to obtain. This transformation proceeds by a cascade involving an intermolecular regioselective allylation of 2-azaallyl anions and a following 2-aza-Cope rearrangement, utilizes easily available reagents and catalysts, tolerates a substantial scope of substrates, and readily leads to various enantioenriched, 1,4-disubstituted homoallylic primary amines.
Direct, intermodular, enantioselective, iridium-catalyzed allylation of carbamates to form carbamate-protected, branched allylic amines
Weix, Daniel J.,Markovic, Dean,Ueda, Mitsuhiro,Hartwig, John F.
supporting information; experimental part, p. 2944 - 2947 (2009/12/05)
The direct reaction between carbamates and achiral allylic carbonates to form branched, conveniently protected primary allylic amines with high regioseiectivity and enantioselectivity Is reported. This process occurs without base or with 0.5 equiv K3PO4 In the presence of a metalacyclic iridium catalyst containing a labile ethylene ligand. The reactions of aryl-, heteroaryl-, and alkyl-substituted allylic carbonates with BocNH 2, FmocNH2, CbZNH2, TrocNH2, TeocNH2, and 2-oxazolidinone occur In good yields, with high selectivity for the branched isomer and high enantioselectivities (98% average ee).
Iridium-catalyzed regio- and enantioselective N-allylation of indoles
Stanley, Levi M.,Hartwig, John F.
supporting information; body text, p. 7841 - 7844 (2010/04/02)
Iridium is blind to C: Highly regio- and enantioselective, iridium-catalyzed N-allylations of indoles, which complement the more common reactivity of indoles as carbon nucleophiles, have been developed (see scheme). These reactions form highly enantioenri
Preparation of Boc-protected cinnamyl-type alcohols: A comparison of the Suzuki-Miyaura coupling, cross-metathesis, and Horner-Wadsworth-Emmons approaches and their merit in parallel synthesis
Stambasky, Jan,Malkov, Andrei V.,Kocovsky, Pavel
experimental part, p. 705 - 732 (2009/04/03)
Three synthetic strategies for the construction of tert-butyl (E)-3-arylprop-2-en-1-ol carbonates are described. Complementary approaches employing Suzuki-Miyaura coupling and cross-metathesis reaction gave moderate yields of the title compounds in one-step, both methods are suitable for high-throughput and parallel chemistry. A detailed investigation into the Suzuki-Miyaura coupling reaction is provided along with the studies on the synthesis of pinacolyl 1-(tert-butyloxycarbonyl)propenol-3-ylboronate, the key building block. Conventional synthesis of the title compounds via the Horner-Wadsworth-Emmons reaction as a key step in a three-step-one-purification protocol was optimized and the results are compared with those of the latter reactions.
Iridium-catalyzed intermolecular allylic etherification with aliphatic alkoxides: Asymmetric synthesis of dihydropyrans and dihydrofurans
Shu, Chutian,Hartwig, John F.
, p. 4794 - 4797 (2007/10/03)
Hindered chiral ethers with one or two stereocenters are now readily available by allylic etherification of primary and secondary alkoxides (see reaction). When an Ir-phosphoramidite complex is used as the catalyst, the reaction proceeds with high regio-, enantio-, and diastereoselectivity. Np = 1-naphthyl.
