3515-93-3Relevant academic research and scientific papers
Synthetic studies toward longeracemine: a SmI2-mediated spirocyclization and rearrangement cascade to construct the 2-azabicyclo[2.2.1]heptane framework
Cox, Joshua B.,Komine, Keita,Lambert, Kyle M.,Savage, Quentin R.,Wood, John L.
, p. 9488 - 9493 (2020)
Longeracemine, a member of theDaphniphyllumfamily of alkaloids contains a novel carbon framework featuring a highly functionalized 2-azabicyclo[2.2.1]heptane core as part of an overall 5/6/5/5/6/5 skeleton. A synthetic intermediate containing the core of longeracemine has been efficiently prepared by employing a stereoselective SmI2-mediated cascade reaction to advance a 7-azabicyclo[2.2.1]heptadiene to a 2-azabicyclo[2.2.1]heptene that is functionally poised for conversion to the natural product.
Photocatalytic Reductive Radical-Polar Crossover for a Base-Free Corey–Seebach Reaction
Crespi, Stefano,Donabauer, Karsten,K?nig, Burkhard,Murugesan, Kathiravan,Rozman, Ur?a
supporting information, p. 12945 - 12950 (2020/09/23)
A metal-free generation of carbanion nucleophiles is of prime importance in organic synthesis. Herein we report a photocatalytic approach to the Corey–Seebach reaction. The presented method operates under mild redox-neutral and base-free conditions giving the desired product with high functional group tolerance. The reaction is enabled by the combination of photo- and hydrogen atom transfer (HAT) catalysis. This catalytic merger allows a C?H to carbanion activation by the abstraction of a hydrogen atom followed by radical reduction. The generated nucleophilic intermediate is then capable of adding to carbonyl electrophiles. The obtained dithiane can be easily converted to the valuable α-hydroxy carbonyl in a subsequent step. The proposed reaction mechanism is supported by emission quenching, radical–radical homocoupling and deuterium labeling studies as well as by calculated redox-potentials and bond strengths.
METHOD OF PRODUCING CYANOALDEHYDE COMPOUND
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Paragraph 0039-0046, (2020/12/15)
PROBLEM TO BE SOLVED: To provide a method of producing a cyanoaldehyde compound by reaction in the presence of a heterogeneous catalyst. SOLUTION: In the method of producing a cyanoaldehyde compound, a gas mixture containing hydrogen gas and carbon monoxide gas is reacted with an unsaturated nitrile compound represented by the formula (1) in the figure in the presence of a heterogeneous catalyst in which a Group 8-11 metal or metal oxide of the fifth or sixth period of the periodic table is supported by a support comprising an oxide of a Group 4-14 element of the fourth period of the periodic table. (In the formula (1), R1 and R2 are each selected from among a hydrogen atom, a C1-8 alkyl group, a cyclohexyl group and a phenyl group.) SELECTED DRAWING: None COPYRIGHT: (C)2021,JPOandINPIT
Multicomponent Catalytic Asymmetric Synthesis of trans-Aziridines
Zhou, Yubai,Gupta, Anil K.,Mukherjee, Munmun,Zheng, Li,Wulff, William D.
, p. 13121 - 13140 (2017/12/26)
A multicomponent trans-aziridination of aldehydes, amines, and diazo compounds with BOROX catalysts is developed. The optimal protocol is slightly different for aryl aldehydes than for aliphatic aldehydes. The key to the success with aryl aldehydes was allowing the catalyst, aldehyde, and amine to react for 20 min before addition of the diazo compound. A variety of 11 different electron-poor and electron-rich aryl aldehydes were screened to give trans-aziridines in 73-90% yield with 82-99% ee and trans/cis selectivities of 19:1 to >99:1. The optimal protocol for the trans-aziridination of aliphatic aldehydes did not require prereaction of the catalyst, aldehyde, and amine, and instead, the diazo compound could be added directly. The scope of the reaction is limited to unbranched aliphatic aldehydes and was tolerant of a number of functional groups including ethers, esters, epoxides, carbamates, and phthalimides. A total of 10 aliphatic aldehydes were examined and found to give trans-aziridines in 60-88% yield with 60-98% ee and trans/cis selectivities of 6:1 to >99:1. Alkenyl aldehydes did not react, but an alkynyl aldehyde gave a 71% yield and 95% ee of an aziridine that was found to be the cis- and not the trans-diastereomer. The aryl and aliphatic aldehydes both gave the trans-aziridines with the same absolute configuration with the same catalyst; however, in those cases where cis-aziridines were formed, the configuration was opposite for those formed from aryl versus aliphatic aldehydes.
Evolution of an oxidative dearomatization enabled total synthesis of vinigrol
Yang, Qingliang,Draghici, Cristian,Njardarson, Jon T.,Li, Fang,Smith, Brandon R.,Das, Pradipta
supporting information, p. 330 - 344 (2014/01/06)
The evolution of the synthetic strategy resulting in a total synthesis of vinigrol is presented. Oxidative dearomatization/intramolecular Diels-Alder cycloaddition has served as the successful cornerstone for all of the approaches. Extensive radical cyclization efforts to form the tetracyclic core resulted in interesting and surprising reaction outcomes, none of which could be advanced to vinigrol. These cyclization obstacles were successfully overcome by using Heck instead of radical cyclizations. The total synthesis features a trifluoroethyl ether protecting group being used for the first time in organic synthesis. The logic of its selection and the group's importance beyond protecting the C8a hydroxyl group is presented along with a discussion of strategies for its removal. Because of the compact tetracyclic cage the route is built around many unusual reaction observations and solutions have emerged. For example, a first of its kind Grob fragmentation reaction featuring a trifluoroethyl leaving group has been uncovered, interesting interrupted selenium dioxide allylic oxidations have been observed as well as intriguing catalyst and counterion dependent directed hydrogenations.
A modular synthesis of teraryl-based α-helix mimetics, part 2: Synthesis of 5-pyridine boronic acid pinacol ester building blocks with amino acid side chains in 3-position
Peters, Martin,Trobe, Melanie,Breinbauer, Rolf
supporting information, p. 2450 - 2456 (2013/03/28)
One of the most common protein-protein interactions (PPI) is the interaction of the α-helix of one protein with the surface of the second one. Terphenylic scaffolds are bioinspired motifs in the inhibition of PPIs and have been identified as suitable α-helix mimetics. One of the challenging aspects of this strategy is the poor solubility of terphenyls under physiological conditions. In the literature pyrrolopyrimidine-, pyrimidine- or pyridazine-based mimetics have been reported to show improved solubility. We present a new convergent strategy for the synthesis of linear pyridine-type teraryls based on a phenylic core unit. A general approach for the synthesis of 3,5-disubstituted pyridine-based boronic acid pinacol esters with amino acid side chains in the 3-position (representing Phe, Leu, Ile, Lys, Asp, Asn) is presented and exploits the functional group tolerance of the Knochel-Grignard reagents. The building blocks have been used in a convergent in situ two-step synthesis of teraryl α-helix mimetics. Tune in: The chemical orthogonality of Knochel's Grignard chemistry enables the synthesis of 3-substituted 5-pyridine-boronic esters with amino acid side chains, which can be used for convenient assembly of teraryl-based α-helix peptide mimetics by Suzuki coupling (see scheme; dppf=1,1′-bis(diphenylphosphino)ferrocene, DME= dimethoxyethane, Tf=trifluoromethanesulfonyl). Copyright
Biobased synthesis of acrylonitrile from glutamic acid
Le Notre, Jerome,Scott, Elinor L.,Franssen, Maurice C. R.,Sanders, Johan P. M.
supporting information; experimental part, p. 807 - 809 (2011/06/22)
Glutamic acid was transformed into acrylonitrile in a two step procedure involving an oxidative decarboxylation in water to 3-cyanopropanoic acid followed by a decarbonylation-elimination reaction using a palladium catalyst. The Royal Society of Chemistry.
NOVEL COMPOUNDS AS CANNABINOID RECEPTOR LIGANDS
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Page/Page column 72, (2010/06/11)
The present application relates to isothiazolylidene containing compounds of Formula (I) wherein R1, R2, R3, R4, and L are as defined in the specification, compositions comprising such compounds, and methods for treating conditions and disorders using such compounds and compositions.
NOVEL COMPOUNDS AS CANNABINOID RECEPTOR LIGANDS
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Page/Page column 56, (2008/12/08)
The present application relates to isothiazolylidene containing compounds of Formula (I) wherein R1, R2, R3, R4, and L are as defined in the specification, compositions comprising such compounds, and methods of treating conditions and disorders using such compounds and compositions.
Modular chiral bidentate phosphonites: Design, synthesis, and application in catalytic asymmetric hydroformylation reactions
Zhao, Baoguo,Peng, Xingao,Wang, Zheng,Xia, Chungu,Ding, Kuiling
experimental part, p. 7847 - 7857 (2009/11/30)
A new class of C2-symmetric chiral bidentate phosphonite ligands has been synthesized in moderate to good yields from readily available starting materials. Application of these air-stable chiral phosphonites in the Rh I-catalyzed asymmetric hydroformylation of styrene derivatives, vinyl acetate, and allyl cyanide afforded the corresponding chiral aldehydes with high regio- and enantioselectivities under mild reaction conditions. The modular nature of the ligands allows fine-tuning of the selectivities through judicious modifications of the substituents on the ligand backbone. X-ray structural analysis of the catalyst precursor suggested that the steric hindrance caused by the protruding remote substituents of the ligands into the vicinity of the metal center might be an important factor for the enantio-control of the reaction, whereas the sense of asymmetric induction can be rationalized on the basis of a trigonal-bipyramidal transition state diagram.
