4646-94-0Relevant academic research and scientific papers
Photoinduced Copper-Catalyzed Asymmetric Decarboxylative Alkynylation with Terminal Alkynes
Dong, Xiao-Yang,Du, Xuan-Yi,Fang, Jia-Heng,Gu, Qiang-Shuai,Li, Zhong-Liang,Liu, Xin-Yuan,Wang, Li-Lei,Xia, Hai-Dong
supporting information, p. 16926 - 16932 (2020/08/25)
We describe a photoinduced copper-catalyzed asymmetric radical decarboxylative alkynylation of bench-stable N-hydroxyphthalimide(NHP)-type esters of racemic alkyl carboxylic acids with terminal alkynes, which provides a flexible platform for the construction of chiral C(sp3)?C(sp) bonds. Critical to the success of this process are not only the use of the copper catalyst as a dual photo- and cross-coupling catalyst but also tuning of the NHP-type esters to inhibit the facile homodimerization of the alkyl radical and terminal alkyne, respectively. Owing to the use of stable and easily available NHP-type esters, the reaction features a broader substrate scope compared with reactions using the alkyl halide counterparts, covering (hetero)benzyl-, allyl-, and aminocarbonyl-substituted carboxylic acid derivatives, and (hetero)aryl and alkyl as well as silyl alkynes, thus providing a vital complementary approach to the previously reported method.
Carbonylative Transformation of Allylarenes with CO Surrogates: Tunable Synthesis of 4-Arylbutanoic Acids, 2-Arylbutanoic Acids, and 4-Arylbutanals
Wu, Fu-Peng,Li, Da,Peng, Jin-Bao,Wu, Xiao-Feng
supporting information, p. 5699 - 5703 (2019/08/01)
In this Communication, procedures for the selective synthesis of 4-arylbutanoic acids, 2-arylbutanoic acids, and 4-arylbutanals from the same allylbenzenes have been developed. With formic acid or TFBen as the CO surrogate, reactions proceed selectively and effectively under carbon monoxide gas-free conditions.
Site-Selective, Remote sp3 C?H Carboxylation Enabled by the Merger of Photoredox and Nickel Catalysis
Sahoo, Basudev,Bellotti, Peter,Juliá-Hernández, Francisco,Meng, Qing-Yuan,Crespi, Stefano,K?nig, Burkhard,Martin, Ruben
supporting information, p. 9001 - 9005 (2019/06/24)
A photoinduced carboxylation of alkyl halides with CO2 at remote sp3 C?H sites enabled by the merger of photoredox and Ni catalysis is described. This protocol features a predictable reactivity and site selectivity that can be modulated by the ligand backbone. Preliminary studies reinforce a rationale based on a dynamic displacement of the catalyst throughout the alkyl side chain.
Copper-catalyzed carboxylation of hydroborated disubstituted alkenes and terminal alkynes with cesium fluoride
Juhl, Martin,Laursen, Simon L. R.,Huang, Yuxing,Nielsen, Dennis U.,Daasbjerg, Kim,Skrydstrup, Troels
, p. 1392 - 1396 (2017/05/24)
A protocol for the hydrocarboxylation of disubstituted alkenes and terminal alkynes providing access to different secondary carboxylic acids and malonic acid derivatives has been developed. This methodology relies on an initial hydroboration using 9-BBN followed by carboxylation with carbon dioxide in the presence of a copper catalyst and the additive, cesium fluoride. Different cyclohexene, styrene, and stilbene derivatives could be utilized, and alkynes could be transformed into their corresponding dicarboxylic acids in good yields. Finally, six different terpenoids were carboxylated using the developed procedure. (Chemical Equation Presented).
Highly enantioselective direct alkylation of arylacetic acids with chiral lithium amides as traceless auxiliaries
Stivala, Craig E.,Zakarian, Armen
supporting information; experimental part, p. 11936 - 11939 (2011/09/19)
A direct, highly enantioselective alkylation of arylacetic acids via enediolates using a readily available chiral lithium amide as a stereodirecting reagent has been developed. This approach circumvents the traditional attachment and removal of chiral auxiliaries used currently for this type of transformation. The protocol is operationally simple, and the chiral reagent is readily recoverable.
N-heterocyclic carbene-mediated enantioselective addition of phenols to unsymmetrical alkylarylketenes
Concellon, Carmen,Duguet, Nicolas,Smith, Andrew D.
supporting information; experimental part, p. 3001 - 3009 (2010/03/26)
Chiral N-heterocyclic carbenes (NHCs) mediate the enantioselective addition of 2-phenylphenol to unsymmetrical alkylarylketenes, delivering α-alkyl-α-arylacetic acid derivatives with good levels of enantiocontrol (up to 84% ee). Enantiodivergent stereochemical outcomes are observed using 2-phe-nylphenol and benzhydrol in the NHC-promoted esterification reaction using a triazolium precatalyst derived from pyroglutamic acid, consistent with distinct mechanistic pathways operating within these processes.
Catalytic enantioselective construction of all-carbon quaternary stereocenters: Synthetic and mechanistic studies of the C-acylation of silyl ketene acetals
Mermerian, Ara H.,Fu, Gregory C.
, p. 5604 - 5607 (2007/10/03)
With the aid of an appropriate chiral catalyst, acyclic silyl ketene acetals react with anhydrides to furnish 1,3-dicarbonyl compounds that bear all-carbon quaternary stereocenters in good ee and yield. Mechanistic studies provide strong support for a catalytic cycle that involves activation of both the electrophile (anhydride → acylpyridinium) and the nucleophile (silyl ketene acetal → enolate).
Enantiospecific synthesis of 4-(4'-methoxyphenyl)-hexan-3-one as precursor for optically active (pS) or (pR) isomer of (Z) or (E)-3-(2'-((N,N-dimethylamino)methylferrocenyl)-4-(4''-methoxyphenyl)-hex-3-ene
Malezieux, Bernard,Gruselle, Michel,Troitskaya, Ludmila,Sokolov, Viatcheslav
, p. 259 - 269 (2007/10/03)
We describe herein an original method for the preparation of enantiomerically pure (Z)- or (E)-3-(2'-((N,N-dimethylamino)methylferrocenyl)-4-(4''-methoxyphenyl)-hex-3-ene possessing a p(S) or p(R) plane of chirality. The key step of the synthesis lies in obtaining enantiomerically pure (R) or (S) 4-(4'-methoxyphenyl)-hexan-3-one whose reaction with the lithiated N,N-dimethylaminomethylferrocene leads to two enantiomerically pure amino-alcohol diastereomers (pS,3S,4R) and (pR,3S,4R), or (pS,3R,4S) and (pR,3R,4S) respectively. Subsequent dehydration yields a mixture of three olefins, namely, two trisubstituted olefins and either the (Z)- or (E)-tetrasubstituted olefin with respect to the starting amino-alcohol diastereomer. Additionally we obtained the enantiomerically pure (R)- and (S)-4-phenyl-hexan-3-one and the corresponding diastereomeric amino-alcohols.
STERICALLY-DRIVEN ANHYDRIDE FORMATION
Belletire, J. L.,Conroy, G. M.
, p. 403 - 416 (2007/10/02)
Oxidative coupling of highly substituted carboxylic acid dianions affords hindered succinic acid derivatives which undergo facile intramolecular anhydride formation.A novel, but low yield, synthetic sequence converts 4'-methoxypropiophenone into diethylstilbestrol.
Process for preparing esters of arylacetic acids from alpha-halo-alkylarylketones
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, (2008/06/13)
Esters of arylacetic acids, more particularly lower alcohol esters of arylacetic acids, including those substituted on the methylene group, are prepared by rearrangement of the corresponding alpha-halo-alkylarylketones with Ag compounds in lower alcohols and in an acid medium. From the alkyl esters so prepared, their respective free acids can be obtained, if desired, by various means such as hydrolysis or the shift with mineral acids of the alkaline salts prepared by reaction with alkali, etc.
