86106-09-4Relevant articles and documents
Iridium-Catalyzed Enantioselective Allylic Substitutions of Racemic, Branched Trichloroacetimidates with Heteroatom Nucleophiles: Formation of Allylic C?O, C?N, and C?S Bonds
Arachchi, Madhawee K.,Nguyen, Hien M.
supporting information, p. 4239 - 4246 (2021/07/16)
A broadly applicable methodology for the regio- and enantioselective construction of branched allylic carbon-heteroatom bonds from racemic, secondary allylic trichloroacetimidates has been developed. The branched allylic substrates undergo dynamic kinetic asymmetric substitution reactions with a number of unactivated anilines and carboxylic acids as well as unactivated aromatic thiols in the presence of a chiral bicyclo[3.3.0]octadiene-ligated iridium catalyst. The allylic C?O, C?N, and C?S bond containing products are obtained in synthetically useful yield and selectivity. Mechanistic studies suggest that the iridium-catalyzed enantioselective substitution reactions of heteroatom nucleophiles with allylic trichloroacetimidate substrates through an outer-sphere nucleophilic addition mechanism. In addition, the chiral diene-ligated iridium catalyst is effective at promoting asymmetric aminations of acyclic secondary anilines. Importantly, this catalytic iridium methodology enables the use of alkyl substituted allylic electrophiles. (Figure presented.).
The Role of Trichloroacetimidate to Enable Iridium-Catalyzed Regio- And Enantioselective Allylic Fluorination: A Combined Experimental and Computational Study
Sorlin, Alexandre M.,Mixdorf, Jason C.,Rotella, Madeline E.,Martin, Robert T.,Gutierrez, Osvaldo,Nguyen, Hien M.
supporting information, p. 14843 - 14852 (2019/10/11)
Asymmetric allylic fluorination has proven to be a robust and efficient methodology with potential applications for the development of pharmaceuticals and practical synthesis for 18F-radiolabeling. A combined computational (dispersion-corrected
Modular Construction of Protected 1,2/1,3-Diols, -Amino Alcohols, and -Diamines via Catalytic Asymmetric Dehydrative Allylation: An Application to Synthesis of Sphingosine
Tanaka, Shinji,Gunasekar, Ramachandran,Tanaka, Tatsuya,Iyoda, Yoko,Suzuki, Yusuke,Kitamura, Masato
, p. 9160 - 9170 (2017/09/11)
A new enantioselective catalysis has been developed for the one-step construction of methylene-bridged chiral modules of 1,2- and 1,3-OH and/or NH function(s) from δ- or λ-OH/NHBoc-substituted allylic alcohols and H2C=O / H2C=NBoc . A protonic nucleophile, either in situ-generated CH2OH or CH2NHBoc, is intramolecularly allylated to furnish eight possible 1,2- or 1,3-O,O, -O,N, -N,O, and -N,N chiral modules equipped with an ethenyl group in high yields and enantioselectivities. The utility of this method has been demonstrated in the five-step synthesis of sphingosine.
Asymmetric Hydroformylation of 4-Vinyl-1,3-dioxolan-2-one
Pongrácz, Péter,Kollár, László
, p. 1430 - 1436 (2017/03/27)
A chiral cyclic carbonate, 4-vinyl-1,3-dioxolan-2-one was used as racemic substrate in asymmetric hydroformylation. The catalysts were formed in situ from “pre-formed” PtCl2(diphosphine) and tin(II) chloride. (2S,4S)-2,4-Bis(diphenylphosphinopentane ((S,S)-BDPP)), (S,S)-2,3-O-izopropylidine-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane ((S,S)-DIOP)), and (R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl ((R)-BINAP)) were used as optically active diphosphine ligands. The platinum-containing catalytic systems provided surprisingly high activity. The hydroformylation selectivities of up to 97% were accompanied by perfect regioselectivity towards the dioxolane-based linear aldehyde. The enantiomeric composition of all components in the reaction mixture was determined and followed throughout the reaction. The unreacted 4-vinyl-1,3-dioxolan-2-one was recovered in optically active form. The kinetic resolution was rationalized using the enantiomeric composition of the substrate and the products.
Expedient synthesis of epigoitrin from L-ascorbic acid
Yang, Jing-Jing,Wu, Jian-Zhong,Qiao, Chunhua
supporting information, p. 1240 - 1244 (2014/04/17)
Epigoitrin is the main bioactive constituent of an important traditional Chinese herbal medicine, Radix isatidis. Reported pharmacological effects of epigoitrin include antiviral, anticancer, and antithyroid activities. Extensive biological exploration of
Preparation of enantioenriched tetraols and triolamines from a common epoxide
Kaviani-Joupari, Makan,Schramm, Michael P.
supporting information, p. 5014 - 5017 (2013/09/02)
We identify a silylcyclopentene oxide that is amenable to several distinct asymmetric catalytic transformations providing access to enantio-enriched tetraol and triol-amines. The sequence employed allows for selective protection of one amine or alcohol from the four heteroatoms that are introduced into the carbon scaffold.
Synthesis and stereospecificity of 4,5-disubstituted oxazolidinone ligands binding to T-box riboswitch RNA
Orac, Crina M.,Zhou, Shu,Means, John A.,Boehm, David,Bergmeier, Stephen C.,Hines, Jennifer V.
scheme or table, p. 6786 - 6795 (2011/12/04)
The enantiomers and the cis isomers of two previously studied 4,5-disubstituted oxazolidinones have been synthesized, and their binding to the T-box riboswitch antiterminator model RNA has been investigated in detail. Characterization of ligand affinities and binding site localization indicates that there is little stereospecific discrimination for binding antiterminator RNA alone. This binding similarity between enantiomers is likely due to surface binding, which accommodates ligand conformations that result in comparable ligand-antiterminator contacts. These results have significant implications for T-box antiterminator-targeted drug discovery and, in general, for targeting other medicinally relevant RNA that do not present deep binding pockets.
"Cassette" in situ enzymatic screening identifies complementary chiral scaffolds for hydrolytic kinetic resolution across a range of epoxides
Dey, Sangeeta,Powell, Douglas R.,Hu, Chunhua,Berkowitz, David B.
, p. 7010 - 7014 (2008/09/17)
(Figure Presented) Put the cassette in: An in situ enzymatic screen can give real-time estimates of the sense and magnitude of enantioselectivity across more than one substrate. Screening identified CoIII-salen catalysts with β-pinene- and α-naphthylalanine-derived chiral scaffolds with broad, yet complementary, substrate specificities. ADH = alcohol dehydrogenase, HL = horse liver, LK = Lactobacillus kefir, salen = (salicylidene) ethylenediamine.
Industrialization of the Microbial Resolution of Chiral C3 and C4 Synthetic Units: From a Small Beginning to a Major Operation, a Personal Account
Kasai, Naoya,Suzuki, Toshio
, p. 437 - 455 (2007/10/03)
This account describes the research and development of the microbial resolution of chiral C3 and C4 synthetic units through to the production stage. These chiral C3 and C4 synthetic units are mainly used for the production of various pharmaceuticals, new materials such as liquid crystals, chiral polymers, and natural compounds as well as in basic chemical research. The research started in 1983 and the industrial plant was built in 1994. The development is still ongoing and is being broadened to include C4 chiral units, chiral propylene glycol, and so on. This project started as simple research on the activated sludge from an epichlorohydrin plant and evolved through many events and much research to an industrial production. We describe the various implications and the flow of events in the research and development through to the production of these chiral C3 and C4 synthetic units.
Highly selective hydrolytic kinetic resolution of terminal epoxides catalyzed by chiral (salen)CoIII complexes. Practical synthesis of enantioenriched terminal epoxides and 1,2-diols
Schaus, Scott E.,Brandes, Bridget D.,Larrow, Jay F.,Tokunaga, Makoto,Hansen, Karl B.,Gould, Alexandra E.,Furrow, Michael E.,Jacobsen, Eric N.
, p. 1307 - 1315 (2007/10/03)
The hydrolytic kinetic resolution (HKR) of terminal epoxides catalyzed by chiral (salen)CoIII complex 1·OAc affords both recovered unreacted epoxide and 1,2-diol product in highly enantioenriched form. As such, the HKR provides general access to useful, highly enantioenriched chiral building blocks that are otherwise difficult to access, from inexpensive racemic materials. The reaction has several appealing features from a practical standpoint, including the use of H2O as a reactant and low loadings (0.2-2.0 mol %) of a recyclable, commercially available catalyst. In addition, the HKR displays extraordinary scope, as a wide assortment of sterically and electronically varied epoxides can be resolved to ≥ 99% ee. The corresponding 1,2-diols were produced in good-to-high enantiomeric excess using 0.45 equiv of H2O. Useful and general protocols are provided for the isolation of highly enantioenriched epoxides and diols, as well as for catalyst recovery and recycling. Selectivity factors (krel) were determined for the HKR reactions by measuring the product ee at ca. 20% conversion. In nearly all cases, krel values for the HKR exceed 50, and in several cases are well in excess of 200.
