128479-27-6Relevant academic research and scientific papers
Enantioselective Decarboxylative Cyanation Employing Cooperative Photoredox Catalysis and Copper Catalysis
Wang, Dinghai,Zhu, Na,Chen, Pinhong,Lin, Zhenyang,Liu, Guosheng
, p. 15632 - 15635 (2017/11/14)
The merger of photoredox catalysis with asymmetric copper catalysis have been realized to convert achiral carboxylic acids into enantiomerically enriched alkyl nitriles. Under mild reaction conditions, the reaction exhibits broad substrate scope, high yields and high enantioselectivities. Furthermore, the reaction can be scaled up to synthesize key chiral intermediates to bioactive compounds.
Beyond benzyl grignards: Facile generation of benzyl carbanions from styrenes
Grigg, R. David,Rigoli, Jared W.,Van Hoveln, Ryan,Neale, Samuel,Schomaker, Jennifer M.
, p. 9391 - 9396 (2012/08/29)
Benzylic functionalization is a convenient approach towards the conversion of readily available aromatic hydrocarbon feedstocks into more useful molecules. However, the formation of carbanionic benzyl species from benzyl halides or similar precursors is far from trivial. An alternative approach is the direct reaction of a styrene with a suitable coupling partner, but these reactions often involve the use of precious-metal transition-metal catalysts. Herein, we report the facile and convenient generation of reactive benzyl anionic species from styrenes. A CuI-catalyzed Markovnikov hydroboration of the styrenic double bond by using a bulky pinacol borane source is followed by treatment with KOtBu to facilitate a sterically induced cleavage of the C-B bond to produce a benzylic carbanion. Quenching this intermediate with a variety of electrophiles, including CO2, CS2, isocyanates, and isothiocyanates, promotes C-C bond formation at the benzylic carbon atom. The utility of this methodology was demonstrated in a three-step, two-pot synthesis of the nonsteroidal anti-inflammatory drug (±)-flurbiprofen. Make or break: The facile generation of benzyl anion equivalents from styrenes has been achieved by using a Cu-catalyzed hydroboration in conjunction with sterically induced cleavage of the C-B bond with tBuOK. Quenching this reactive intermediate with heteroallene electrophiles yields benzylic C-C bond formation (see scheme), and the utility of this methodology has been demonstrated by a synthesis of the nonsteroidal anti-inflammatory drug (±)-flurbiprofen. Copyright
Kinetic resolution of racemic α-arylalkanoic acids with achiral alcohols via the asymmetric esterification using carboxylic anhydrides and acyl-transfer catalysts
Shiina, Isamu,Nakata, Kenya,Ono, Keisuke,Onda, Yu-Suke,Itagaki, Makoto
supporting information; experimental part, p. 11629 - 11641 (2010/10/04)
A variety of optically active carboxylic esters are produced by the kinetic resolution of racemic α-substituted carboxylic acids using achiral alcohols, aromatic or aliphatic carboxylic anhydrides, and chiral acyl-transfer catalysts. The combination of 4-methoxybenzoic anhydride (PMBA) or pivalic anhydride with the modified benzotetramisole-type catalyst ((S)-β-Np-BTM) is the most effective for promotion of the enantioselective coupling reaction between racemic carboxylic acids and a novel nucleophile, bis(α-naphthyl) methanol, to give the corresponding esters with high ees. This protocol was successfully applied to the production of nonracemic nonsteroidal anti-inflammatory drugs from racemic compounds utilizing the transacylation process to generate the mixed anhydrides from the acid components with the suitable carboxylic anhydrides.
Alternative synthesis of 2-arylpropanoic acids from enolate and aryl halides
Ferrayoli, Carlos G.,Palacios, Sara M.,Alonso, Ruben A.
, p. 1635 - 1638 (2007/10/02)
Arylpropanoic acids, a type of non-steroidal antiinflammatory drug, have been prepared in liquid ammonia by photo-radical nucleophilic substitution of halogenoarenes with sodium N,N-dimethylacetamide enolate followed by methylation and hydrolysis.Rapid substitution occured in many cases with good to excellent yields of arylpropanoic acids.The title compounds have also been prepared by arylation of sodium acetone enolate with methylation and oxidation in a haloform reaction.
Phenanthrylalkanoic acids, V. A useful access to α-methylphenanthreneacetic acids
Balo,Fernandez,Gomez,Gonzalez,Lopez
, p. 967 - 969 (2007/10/02)
A very simple one-pot monomethylation of phenanthreneacetic acids 2 or of their methyl esters 1 yields α-methylphenanthreneacetic acids 3 in good yield. Alternatively, the process may be extended to the preparation of the corresponding α-arylisobutyric acids 4.
