25597-16-4Relevant academic research and scientific papers
Stereospecific Synthesis of Substituted Aziridines by a Crystal-to-Crystal Photodenitrogenation of δ2-1,2,3-Triazolines
Chung, Tim S.,Lopez, Steven A.,Houk,Garcia-Garibay, Miguel A.
, p. 4568 - 4571 (2015)
Crystalline cis- or trans-δ2-1,2,3-triazolines prepared by highly stereospecific and regioselective hydrogen bonding-catalyzed dipolar cycloaddition of activated cis- or trans-alkenes with aryl azides undergo a highly stereospecific photodenitrogenation to form the corresponding cis- or trans- azidirines in high chemical yields. While examples involving disubstituted and trisubstituted triazolines highlight steric challenges encountered in the dipolar cycloaddition reaction, the stereochemical control exerted by the crystalline lattice is enhanced by bulky substituents in the triazoline precursors to generate aziridines photochemically.
PREPARATION OF TRIFLUOROMETHYLATED ALLYLIC ALCOHOLS FROM TRIFLUOROACETALDEHYDE AND ORGANOMETALLIC COMPOUNDS
Ishikawa, Nobuo,Koh, Moon Gyu,Kitazume, Tomoya,Choi, Sam Kwon
, p. 419 - 430 (1984)
A number of allylic alcohols bearing a trifluoromethyl group at the α- or γ-position, and α-trifluoromethylated γ-enols and -ynols were prepared by the reaction of trifluoroacetaldehyde with a variety of organometallic compounds.Most of the Reformatsky- or Grignard-type reactions required promotion by ultrasonic irradiation.
Stereoselective aldol reaction of glutarimides using pseudo C2 symmetry
Watanabe, Yohsuke,Yamazaki, Takashi,Kubota, Toshio
, p. 268 - 271 (2010)
(Figure presented) The boron aldol reaction of β-substituted glutaric imldes bearing an oxazolidinone-based auxiliary proceeds with excellent diastereoselectivity; switching the tertiary amine employed between /-Pr 2EtN or Et3N affor
NMR at earth's magnetic field using para-hydrogen induced polarization
Hamans, Bob C.,Heerschap, Arend,Andreychenko, Anna,Wijmenga, Sybren S.,Tessari, Marco
, p. 224 - 228,5 (2011)
A method to achieve NMR of dilute samples in the earth's magnetic field by applying para-hydrogen induced polarization is presented. Maximum achievable polarization enhancements were calculated by numerically simulating the experiment and compared to the experimental results and to the thermal equilibrium in the earth's magnetic field. Simultaneous 19F and 1H NMR detection on a sub-milliliter sample of a fluorinated alkyne at millimolar concentration (～1018 nuclear spins) was realized with just one single scan. A highly resolved spectrum with a signal/noise ratio higher than 50:1 was obtained without using an auxiliary magnet or any form of radio frequency shielding.
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
supporting information, 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.
PROCESS FOR PREPARATION OF 4,4,4- TRIFLUOROBUT-2-EN-1-OL AND INTERMEDIATE THEREOF
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Page/Page column 11, (2020/07/31)
The present invention provides a process for preparation of 4,4,4- trifluorobut-2-en-1-ol from alkyl 4,4,4-trifluorobut-2-enoate and also provides one step process for preparation of alkyl 4,4,4-trifluorobut-2-enoate from corresponding hydroxy derivative using mild and easily available reagents.
Synthesis method for 4,4,4-trifluoro-crotonates
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Paragraph 0037; 0040; 0041; 0042; 0044; 0049; 0054; 0060, (2019/01/16)
The invention relates to a synthesis method for 4,4,4-trifluoro-crotonates. The problems that in the prior art, the conversion rate of 3,3,3-trifluoro-allylene is low, and the selectivity of 4,4,4-trifluoro-crotonates is low are mainly solved. The preparing method for the 4,4,4-trifluoro-crotonates includes the step that the 3,3,3-trifluoro-allylene, materials of carbon monoxide and alcohol and acatalyst composition are subjected to a contact reaction to obtain the 4,4,4-trifluoro-crotonates, wherein the catalyst composition comprises a rhodium complex and a high-valence-metal-cation-ocene diphosphonic compound in the technical scheme; the technical problems are well solved, and the synthesis method can be used for industrial production of the 4,4,4-trifluoro-crotonates.
Stereospecific photochemistry of Δ2-1,2,3-triazolines in solution and in the solid state: Scope and mechanistic studies
Chung, Tim S.,Xue, Yang,Carranza, Alberto,Garcia-Garibay, Miguel A.
, p. 1458 - 1463 (2017/09/23)
The stereospecific photochemistry of ten N-aryl-substituted cis- or trans-Δ2-1,2,3-triazolines to form the corresponding cis- or trans-aziridines was investigated both in solution and in the solid-state. We found that photochemical reactions in the solid state are more stereospecific than in solution for the 8 crystalline Δ2-1,2,3-triazolines. Additionally, triplet sensitization for some triazolines results in triplet biradicals, which provide the more thermodynamically favored trans-aziridine regardless of the starting triazoline stereochemistry. Product analyses as a function of temperature and solvent polarity suggest that the electronic excitation of the Δ2-1,2,3-triazolines results in the formation of a 1,3-biradical intermediate.
METHOD FOR PREPARATION OF FLUORO, CHLORO AND FLUOROCHLORO ALKYLATED COMPOUNDS BY HOMOGENEOUS CATALYSIS
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Page/Page column 21; 22, (2016/06/01)
The invention discloses a method for preparation of fluoro, chloro and fluorochloro alkylated compounds by homogeneous Pd catalyzed fluoro, chloro and fluorochloro alkylation with fluoro, chloro and fluorochloroalkyl halides in the presence of di(1-adamantyl)-n-butylphosphine and in the presence of 2,2,6,6-tetramethylpiperidine 1-oxyl.
Decarboxylative and Denitrative Trifluoromethylation for the Synthesis of Cvinyl-CF3 Compounds with Togni (II) Reagent
Ma, Jing-Jing,Yi, Wen-Bin,Lu, Guo-Ping,Cai, Chun
supporting information, p. 3447 - 3452 (2016/01/25)
A highly efficient dimethylformamide (DMF)-promoted decarboxylative trifluoromethylation of α,β-unsaturated carboxylic acids with Togni (II) reagent under metal-free conditions has been developed. The reactions showed good yields, high stereoselectivities and excellent functional group tolerance. Mechanistic studies confirmed that free-radical processes were involved in this system since the CF3 radical had been clearly trapped by scavengers. This method has been extended to the denitrative trifluoromethylation of β-nitrostyrenes in the presence of an iron(III) catalyst.
