18922-06-0Relevant articles and documents
Cycloaddition Reactions of Cobalt-Complexed Macrocyclic Alkynes: The Transannular Pauson-Khand Reaction
Karabiyikoglu, Sedef,Boon, Byron A.,Merlic, Craig A.
, p. 7732 - 7744 (2017)
The Pauson-Khand reaction is a powerful tool for the synthesis of cyclopentenones through the efficient [2 + 2 + 1] cycloaddition of dicobalt alkyne complexes with alkenes. While intermolecular and intramolecular variants are widely known, transannular versions of this reaction are unknown and the basis of this study. Macrocyclic enyne and dienyne complexes were readily synthesized by palladium(II)-catalyzed oxidative macrocyclizations of bis(vinyl boronate esters) or ring-closing metathesis reactions followed by complexation with dicobalt octacarbonyl. Several reaction modalities of these macrocyclic complexes were uncovered. In addition to the first successful transannular Pauson-Khand reactions, other intermolecular and transannular cycloaddition reactions included intermolecular Pauson-Khand reactions, transannular [4 + 2] cycloaddition reactions, intermolecular [2 + 2 + 2] cycloaddition reactions, and intermolecular [2 + 2 + 1 + 1] cycloaddition reactions. The structural and reaction requirements for each process are presented.
Synthesis of a novel ethylene-bis(tetrahydroindenyl) ligand containing a functionalized four-carbon tether
Panarello, Anthony P.,Khinast, Johannes G.
, p. 4095 - 4098 (2003)
In this work we present an efficient synthesis of a novel ethylene-bis(2-methyl-tetrahydroindenyl) ligand, 2b, containing a tethered functional group. The tethered functional group may enable heterogenization of the homogeneous ligand on various solid sup
Concise synthesis of (4R,9Z)-octadec-9-en-4-olide, the female sex pheromone of Janus integer
Mori, Kenji
, p. 2040 - 2044 (2005)
(4R,9Z)-Octadec-9-en-4-olide, the female sex pheromone of the currant stem girdler (Janus integer), was synthesized in gram quantities by employing Sharpless asymmetric dihydroxylation (AD) and Jacobsen hydrolytic kinetic resolution (HKR). Crystalline (R)-hexadec-7-yne-1,2-diol (87% ee), obtained by AD and purified by recrystallization, was converted into (R)-1,2-epoxyhexadec-7- yne (87%ee), which was further purified to 96% ee by HKR. The epoxide was converted into the target lactone in 14% overall yield based on hex-5-en-1-ol (11 steps). Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
Computationally Guided Catalyst Design in the Type i Dynamic Kinetic Asymmetric Pauson-Khand Reaction of Allenyl Acetates
Burrows, Lauren C.,Jesikiewicz, Luke T.,Lu, Gang,Geib, Steven J.,Liu, Peng,Brummond, Kay M.
, p. 15022 - 15032 (2017)
The Rh(I)-catalyzed allenic Pauson-Khand reaction (APKR) is an efficient, redox-neutral method of synthesizing α-acyloxy cyclopentenones. An enantioselective APKR could provide access to chiral, nonracemic α-acyloxy and α-hydroxy cyclopentenones and their corresponding redox derivatives, such as thapsigargin, a cytotoxic natural product with potent antitumor activity. Rapid scrambling of axial chirality of allenyl acetates in the presence of Rh(I) catalysts enables the conversion of racemic allene to enantiopure cyclopentenone product in a dynamic kinetic asymmetric transformation (DyKAT). A combined experimental and computational approach was taken to develop an effective catalytic system to achieve the asymmetric transformation. The optimization of the denticity, and steric and electronic properties of the ancillary ligand (initially (S)-MonoPhos, 58:42 er), afforded a hemilabile bidentate (S)-MonoPhos-alkene-Rh(I) catalyst that provided α-acyloxy cyclopentenone product in up to 14:86 er. Enantioselectivity of the Rh(I)-(S)-MonoPhos-alkene catalyst was rationalized using ligand-substrate steric interactions and distortion energies in the computed transition states. This asymmetric APKR of allenyl acetates is a rare example of a Type I DyKAT reaction of an allene, the first example of DyKAT in a cyclocarbonylation reaction, and the first catalyst-controlled enantioselective APKR.
Synthesis and characterization of light-fluorous NHC-ligands and their palladium complexes
Horváth, István T.,Lo, Angel S. W.,Yiu, Ken S. M.
, (2021)
Light-fluorous ponytails containing perfluoro-n-propyl, perfluoro-n-butyl and perfluoro-t-butoxy groups were used to synthesize light-fluorous α-olefins, branched dialkyl iodides, alkyl triflates, alkyl imidazoles, and dialkyl imidazolium salts. The latte
A Systematic Study of Unsaturation in Lipid Nanoparticles Leads to Improved mRNA Transfection In Vivo
Lee, Sang M.,Cheng, Qiang,Yu, Xueliang,Liu, Shuai,Johnson, Lindsay T.,Siegwart, Daniel J.
, p. 5848 - 5853 (2021)
Lipid nanoparticles (LNPs) represent the leading concept for mRNA delivery. Unsaturated lipids play important roles in nature with potential for mRNA therapeutics, but are difficult to access through chemical synthesis. To systematically study the role of unsaturation, modular reactions were utilized to access a library of 91 amino lipids, enabled by the synthesis of unsaturated thiols. An ionizable lipid series (4A3) emerged from in vitro and in vivo screening, where the 4A3 core with a citronellol-based (Cit) periphery emerged as best. We studied the interaction between LNPs and a model endosomal membrane where 4A3-Cit demonstrated superior lipid fusion over saturated lipids, suggesting its unsaturated tail promotes endosomal escape. Furthermore, 4A3-Cit significantly improved mRNA delivery efficacy in vivo through Selective ORgan Targeting (SORT), resulting in 18-fold increased protein expression over parent LNPs. These findings provide insight into how lipid unsaturation promotes mRNA delivery and demonstrate how lipid mixing can enhance efficacy.
MACROCYCLIC PAD4 INHIBITORS USEFUL AS IMMUNOSUPPRESSANT
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Page/Page column 107-108, (2021/08/13)
The present invention provides compounds of Formula (I) useful as inhibitors of PAD4, compositions thereof, and methods of treating PAD4-related disorders, (I) wherein ring A, A1, A2, A3, A4, Q, R1, R
Divinylcarbinol Desymmetrization Strategy: A Concise and Reliable Approach to Chiral Hydroxylated Fatty Acid Derivatives
Sugimoto, Kenji,Kobayashi, Ami,Kohyama, Aki,Sakai, Haruka,Matsuya, Yuji
, p. 3970 - 3980 (2021/03/01)
By the aid of the catalytic desymmetrization of divinylcarbinol as one-pot asymmetric induction and protection of olefin, asymmetric total syntheses of two chiral hydroxylated fatty acid derivatives were successfully achieved. The desired stereoisomers could be concisely prepared in mild conditions in a highly convergent manner. Thus, this novel strategy can help stereochemical elucidations of natural products, which have difficulties in spectroscopic stereochemical analyses due to their local symmetries in the vicinities of the stereogenic secondary hydroxyl units.
Ni-Catalyzed Carboxylation of Aziridines en Route to β-Amino Acids
Davies, Jacob,Janssen-Müller, Daniel,Zimin, Dmitry P.,Day, Craig S.,Yanagi, Tomoyuki,Elfert, Jonas,Martin, Ruben
supporting information, p. 4949 - 4954 (2021/04/07)
A Ni-catalyzed reductive carboxylation of N-substituted aziridines with CO2 at atmospheric pressure is disclosed. The protocol is characterized by its mild conditions, experimental ease, and exquisite chemo- and regioselectivity pattern, thus unlocking a new catalytic blueprint to access β-amino acids, important building blocks with considerable potential as peptidomimetics.
Diethylzinc-Mediated Radical 1,2-Addition of Alkenes and Alkynes
Li, Xin,He, Songtao,Song, Qiuling
supporting information, p. 2994 - 2999 (2021/05/04)
A novel diethylzinc-mediated radical 1,2-addition of perfluoroalkyl iodides to unactivated alkenes and alkynes is presented, which demonstrates a novel way to generate an ethyl difluoroacetate radical. This method is highly efficient and gives full conversions of the substrates, high yields of the products, and negligible byproducts and requires no column chromatography purifications. The mild conditions enable this protocol to exhibit excellent functional group compatibility.
