14815-73-7Relevant articles and documents
Asymmetric Aminations and Kinetic Resolution of Acyclic α-Branched Ynones
He, Faqian,Shen, Guosong,Yang, Xiaoyu
supporting information, p. 15 - 20 (2021/11/20)
An efficient method for asymmetric synthesis of acyclic α-tertiary amine derivatives has been achieved through enantioselective aminations of α-branched ynones with azodicarboxylates enabled by chiral phosphoric acid catalysis. Moreover, kinetic resolution of racemic starting material was realized under these conditions, which gave access to valuable enantioenriched α-substituted ketones. A wide array of α-aryl and alkyl-substitutions, and the substituted alkynyl groups were well compatible with this method, producing both the amination products and the recovered ketones with good to high enantioselectivities.
syn-Selective Michael Reaction of α-Branched Aryl Acetaldehydes with Nitroolefins Promoted by Squaric Amino Acid Derived Bifunctional Br?nsted Bases
Campano, Teresa E.,García-Urricelqui, Ane,Mielgo, Antonia,Palomo, Claudio,de Cózar, Abel
supporting information, p. 3604 - 3612 (2021/07/26)
Here we describe a direct access to 2,2,3-trisubstituted syn γ-nitroaldehydes by addition of α-branched aryl acetaldehydes to nitroolefins promoted by a cinchona based squaric acid-derived amino acid peptide. Different α-methyl arylacetaldehydes react with β-aromatic and β-alkyl nitroolefins to afford the Michael adducts in high enantioselectivity and syn-selectivity. NMR experiments and DFT calculations predict the reaction to occur through the intermediacy of E-enolate. The interaction between the substrates and the catalyst follows Pápai's model, wherein an intramolecular H-bond interaction in the catalyst between the NH group of one of the tert-leucines and the squaramide oxygen seems to be key for discrimination of the corresponding reaction transition states.
Palladium-Catalyzed Carbocyclizations of Unactivated Alkyl Bromides with Alkenes Involving Auto-tandem Catalysis
Venning, Alexander R. O.,Kwiatkowski, Megan R.,Roque Pe?a, Joan E.,Lainhart, Brendan C.,Guruparan, Akil A.,Alexanian, Erik J.
supporting information, p. 11595 - 11600 (2017/08/30)
The development of a general catalytic system for the palladium-catalyzed carbocyclization of unactivated alkyl bromides with alkenes is described. This approach uses a commercially available bisphosphine ligand and avoids the use of carbon monoxide atmosphere present in prior studies involving alkyl iodides. Detailed mechanistic studies of the transformation are performed, which are consistent with auto-tandem catalysis involving atom-transfer radical cyclization followed by catalytic dehydrohalogenation. These studies also suggest that reactions involving alkyl iodides may proceed through a metal-initiated, rather than metal-catalyzed, radical chain process.
Development of an O-Vinylation-Ring-Closing Metathesis Strategy to Access 3,3′-3,4-Dihydropyrans
Dechert-Schmitt, Anne-Marie,Cabral, Shawn,Kung, Daniel W.
supporting information, p. 2611 - 2615 (2016/11/11)
Dihydropyrans are common structural motifs that appear in both natural products and pharmaceuticals and are intermediates for the synthesis of tetrahydropyrans. Currently, no reports exist in the literature for the synthesis of 3,3′-differentially disubst
IMMUNOREGULATORY AGENTS
-
Paragraph 0552, (2016/06/01)
Compounds that modulate the oxidoreductase enzyme indoleamine 2,3- dioxygenase, and compositions containing the compounds, are described herein. The use of such compounds and compositions for the treatment and/or prevention of a diverse array of diseases,
Synthesis of α-aryl esters and nitriles: Deaminative coupling of α-aminoesters and α-aminoacetonitriles with arylboronic acids
Wu, Guojiao,Deng, Yifan,Wu, Chaoqiang,Zhang, Yan,Wang, Jianbo
supporting information, p. 10510 - 10514 (2016/02/18)
Transition-metal-free synthesis of α-aryl esters and nitriles using arylboronic acids with α-aminoesters and α-aminoacetonitriles, respectively, as the starting materials has been developed. The reaction represents a rare case of converting C(sp3)-N bonds into C(sp3)-C(sp2) bonds. The reaction conditions are mild, demonstrate good functional-group tolerance, and can be scaled up. Touch base: A transition-metal-free protocol for the synthesis of α-aryl esters and nitriles by deaminative coupling is presented. Strong bases and transition-metal catalysts are not needed. The new synthetic method uses readily available starting materials and demonstrates wide substrate scope.
First iodine-catalyzed deallylation of reactive allyl methylene esters
Nawghare, Beena R.,Lokhande, Pradeep D.
, p. 1955 - 1963 (2013/06/05)
C-Allyl cleavage has been developed using the inexpensive and mild reagent iodine in dimethylsulfoxide. A variety of compounds with active methylene groups were C-deallylated using this reagent. This method is efficient and operationally simple in comparison to the methods using transition-metal complexes. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
Reactivity of terminal phenylpentenes in a ruthenium-catalyzed cross-metathesis reaction: Construction of linear bifunctional C-8 alkenes
Stefane, Bogdan,Pozgan, Franc
, p. 633 - 640 (2013/07/26)
In the present study the behavior of 1-functionalized 2-phenylpent-4-enes in the presence of ruthenium-based metathesis catalysts was investigated. The experimental observations revealed that the outcome of the reaction depends very much on the combination of olefinic partners used in the reaction; only certain combinations delivered satisfactory amounts of unsymmetrical cross-metathesis products, i.e., bifunctional C-8 alkenes.
Carbon-carbon bond-forming reactions of α-carbonyl carbocations: Exploration of a reversed-polarity equivalent of enolate chemistry
Lai, Ping-Shan,Dubland, Joshua A.,Sarwar, Mohammed G.,Chudzinski, Michael G.,Taylor, Mark S.
, p. 7586 - 7592 (2011/10/12)
Carbon-carbon bond-forming reactions of putative α-carbonyl carbocation intermediates generated by Lewis acid- or silver-promoted ionizations of toluenesulfonate or halide leaving groups are described. This under-exploited mode of reactivity represents an 'umpolung' of conventional enolate chemistry, and enables C-C bond construction in both intra- and intermolecular contexts. Attempts to develop diastereoselective variants of this process using chiral ester and oxazolidinone-based auxiliaries are discussed.
Diastereoselective access to trans -2-substituted cyclopentylamines
Joosten, Antoine,Lambert, Emilie,Vasse, Jean-Luc,Szymoniak, Jan
supporting information; experimental part, p. 5128 - 5131 (2011/01/05)
A highly diastereoselective synthesis of trans-2-substituted cyclopentylamines via a tandem hydrozirconation/Lewis acid-mediated cyclization sequence applied to butenyl oxazolidines is described. The method allows an easy preparation of diversely substituted cyclopentylamines which appear to be useful synthetic intermediates. This was further illustrated by the syntheses of (±)-Rodocaine, (±)-trans-pentacin, and enantiomerically enriched trans-cyclopentane-1,2-diamine.