41965-71-3Relevant academic research and scientific papers
Anionic Bisoxazoline Ligands Enable Copper-Catalyzed Asymmetric Radical Azidation of Acrylamides
Wu, Lianqian,Zhang, Zhihan,Wu, Dunqi,Wang, Fei,Chen, Pinhong,Lin, Zhenyang,Liu, Guosheng
, p. 6997 - 7001 (2021/02/26)
Asymmetric radical azidation for the synthesis of chiral alkylazides remains a tremendous challenge in organic synthesis. We report here an unprecedented highly enantioselective radical azidation of acrylamides catalyzed by 1 mol % of a copper catalyst. The substrates were converted to the corresponding alkylazides in high yield with good-to-excellent enantioselectivity. Notably, employing an anionic cyano-bisoxazoline (CN-Box) ligand is crucial to generate a monomeric CuII azide species, rather than a dimeric CuII azide intermediate, for this highly enantioselective radical azidation.
Direct Regio- and Diastereoselective Synthesis of δ-Lactams from Acrylamides and Unactivated Alkenes Initiated by RhIII-Catalyzed C?H Activation
Lee, Sumin,Rovis, Tomislav,Semakul, Natthawat
supporting information, p. 4965 - 4969 (2020/02/20)
We report a RhIII-catalyzed regio- and diastereoselective synthesis of δ-lactams from readily available acrylamide derivatives and unactivated alkenes. The reaction provides a rapid route to a diverse set of δ-lactams in good yield and stereoselectivity, which serve as useful building blocks for substituted piperidines. The regioselectivity of the reaction with unactivated terminal alkene is significantly improved by using Cpt ligand on the RhIII catalyst. The synthetic utility of the reaction is demonstrated by the preparation of a potential drug candidate containing a trisubstituted piperidine moiety. Mechanistic studies show that the reversibility of the C?H activation depends on the choice of Cp ligand on the RhIII catalyst. The irreversible C?H activation is observed and becomes turnover-limiting with [CptRhCl2]2 as catalyst.
Cobalt(III)-Catalyzed Directed C-H Allylation
Gensch, Tobias,Vásquez-Céspedes, Suhelen,Yu, Da-Gang,Glorius, Frank
supporting information, p. 3714 - 3717 (2015/08/18)
The cobalt(III)-catalyzed allylation was developed for amide-directed C-H activation of arenes, heteroarenes, and olefins. A variety of allyl sources can be employed to introduce this useful functional group.
Cyclobutane Synthesis and Fragmentation. A Cascade Route to the Lycopodium Alkaloid (-)-Huperzine A
White, James D.,Li, Yang,Kim, Jungchul,Terinek, Miroslav
, p. 11806 - 11817 (2015/12/11)
An asymmetric total synthesis of the nootropic alkaloid (-)-huperzine A was completed using a cascade sequence initiated by an intramolecular aza-Prins reaction and terminated by a stereoelectronically guided fragmentation of a cyclobutylcarbinyl cation as the key step in assembling the bicyclo[3.3.1]nonene core of the natural product. Intramolecular [2 + 2]-photocycloaddition of the crotyl ether of (S)-4-hydroxycyclohex-2-enone afforded a bicyclo[4.2.0]octanone containing an embedded tetrahydrofuran in which the cyclohexanone moiety was converted to a triisopropylsilyl enol ether and functionalized as an allylic azide. The derived primary amine was acylated with α-phenylselenylacrylic acid, and the resulting amide was reacted with trimethylaluminum to give a [2 + 2]-cycloadduct, which underwent retroaldol fission to produce a fused α-phenylselenyl δ-lactam. Periodate oxidation of this lactam led directly to an α-pyridone, which was converted to a fused 2-methoxypyridine. Reductive cleavage of the activated "pyridylic" C-O bond in this tetracycle and elaboration of the resultant hydroxy ketone to a diketone was followed by chemoselective conversion of the methyl ketone in this structure to an endo isopropenyl group. Condensation of the remaining ketone with methyl carbamate in the presence of acid initiated the programmed cascade sequence and furnished a known synthetic precursor to huperzine A. Subsequent demethylation of the carbamate and the methoxypyridine, accompanied by in situ decarboxylation of the intermediate carbamic acid, gave (-)-huperzine A.
A novel synthesis of (-)-huperzine A via tandem intramolecular aza-Prins cyclization-cyclobutane fragmentation
White, James D.,Li, Yang,Kim, Jungchul,Terinek, Miroslav
supporting information, p. 882 - 885 (2013/03/28)
The acetylcholinesterase inhibitor (-)-huperzine A was synthesized from (S)-4-hydroxycyclohex-2-enone in 17 steps by a route that involved two cyclobutane fragmentations. The first of these employed a retro-aldol cleavage to generate the α-pyridone ring o
Rh(III)-catalyzed halogenation of vinylic C-H bonds: Rapid and general access to Z-halo acrylamides
Kuhl, Nadine,Schroeder, Nils,Glorius, Frank
supporting information, p. 3860 - 3863 (2013/09/02)
Herein, the regio- and stereoselective iodination, along with some examples for the bromination, of readily available acrylamides to access a variety of differently substituted Z-haloacrylic acid derivatives is reported. The reaction proceeds under mild conditions via a Rh(III)-catalyzed C-H-activation/ halogenation mechanism and represents a rare example of a direct halogenation of electron-poor acrylic acid derivatives.
Nematicidal alkenanilides
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, (2008/06/13)
A method is described for the control of nematodes in agricultural crops which comprises applying to the situs of infestation a nematicidal composition containing as active ingredient a compound of the formula STR1 wherein R1 and R2 are hydrogen, lower alkyl, or halogen, X is hydrogen or halogen, n is 1 or 2, Y is hydrogen, lower alkyl, halogen, trifluoromethyl, lower alkoxy, lower alkylthio, and nitro when n is 1, and halogen when n is 2, with the proviso that at least 1 of R1, R2, and X must be halogen. Preparation of active ingredient compounds is described, and nematicidal utility of compositions is exemplified.
