104015-38-5Relevant academic research and scientific papers
Amide/Ester Cross-Coupling via C-N/C-H Bond Cleavage: Synthesis of β-Ketoesters
Chen, Jiajia,Joseph, Devaneyan,Xia, Yuanzhi,Lee, Sunwoo
, p. 5943 - 5953 (2021/04/02)
Activated primary, secondary, and tertiary amides were coupled with enolizable esters in the presence of LiHMDS to obtain good yields of β-ketoesters at room temperature. Notably, this protocol provides an efficient, mild, and high chemoselectivity method
Chemo- and Enantioselective Oxidative α-Azidation of Carbonyl Compounds
Hattori, Yuhei,Ishihara, Kazuaki,Sahara, Naoto,Tsukahara, Mayuko,Uyanik, Muhammet
, p. 17110 - 17117 (2020/08/10)
We report high-performance I+/H2O2 catalysis for the oxidative or decarboxylative oxidative α-azidation of carbonyl compounds by using sodium azide under biphasic neutral phase-transfer conditions. To induce higher reactivity especially for the α-azidation of 1,3-dicarbonyl compounds, we designed a structurally compact isoindoline-derived quaternary ammonium iodide catalyst bearing electron-withdrawing groups. The nonproductive decomposition pathways of I+/H2O2 catalysis could be suppressed by the use of a catalytic amount of a radical-trapping agent. This oxidative coupling tolerates a variety of functional groups and could be readily applied to the late-stage α-azidation of structurally diverse complex molecules. Moreover, we achieved the enantioselective α-azidation of 1,3-dicarbonyl compounds as the first successful example of enantioselective intermolecular oxidative coupling with a chiral hypoiodite catalyst.
Asymmetric Synthesis of α-Chloro-α-halo Ketones by Decarboxylative Chlorination of α-Halo-β-ketocarboxylic Acids
Iwasa, Seiji,Kitahara, Kazumasa,Mizutani, Haruna,Shibatomi, Kazutaka
, p. 4385 - 4392 (2019/11/21)
Chiral α-chloro-α-fluoro ketones were synthesized by enantio-selective decarboxylative chlorination of α-chloro-β-ketocarboxylic acids in the presence of a chiral amine catalyst. The reaction yielded the corresponding α-chloro-α-fluoro ketones with modera
Williamson Ether Synthesis with Phenols at a Tertiary Stereogenic Carbon: Formal Enantioselective Phenoxylation of β-Keto Esters
Shibatomi, Kazutaka,Kotozaki, Manato,Sasaki, Nozomi,Fujisawa, Ikuhide,Iwasa, Seiji
supporting information, p. 14095 - 14098 (2015/09/28)
The enantioselective formation of α-aryloxy-β-keto esters is described for the first time. Lewis acid catalyzed enantioselective chlorination of β-keto esters and subsequent SN2 reactions with phenols yielded α-aryloxy-β-keto esters with up to 96 % ee. Favorskii rearrangement of α-chloro-β-keto esters was also found to give 1,2-diesters with slightly reduced enantiopurity.
Iron(iii)-salan complexes catalysed highly enantioselective fluorination and hydroxylation of β-keto esters and N-Boc oxindoles
Gu, Xin,Zhang, Yan,Xu, Zhen-Jiang,Che, Chi-Ming
, p. 7870 - 7873 (2014/07/08)
Chiral iron(iii)-salan complexes catalysed highly enantioselective α-fluorination and α-hydroxylation of β-keto esters and N-Boc oxindoles to give the corresponding products in high yields and good-to-excellent ee values under mild reaction conditions. This journal is the Partner Organisations 2014.
Highly enantioselective chlorination of β-keto esters and subsequent SN2 displacement of tertiary chlorides: A flexible method for the construction of quaternary stereogenic centers
Shibatomi, Kazutaka,Soga, Yoshinori,Narayama, Akira,Fujisawa, Ikuhide,Iwasa, Seiji
supporting information; body text, p. 9836 - 9839 (2012/07/30)
Highly enantioselective chlorination of β-oxo esters and subsequent stereospecific substitution of tertiary chlorides are described. Enantioselective chlorination of β-keto esters and malonates was performed using a chiral Lewis acid catalyst prepared from Cu(OTf)2 and the newly developed spirooxazoline ligand 2 to yield the desired α-chlorinated products with high enantioselectivity (up to 98% ee). Nucleophilic substitution of the resulting chlorides proceeded smoothly to afford a variety of chiral molecules such as α-amino, α-alkylthio, and α-fluoro esters, without loss of enantiopurity. The results of X-ray crystallographic analysis proved that Walden inversion occurs at the chlorinated tertiary carbon center. These results supported the fact that the substitution proceeds via an S N2 mechanism.
Delineating origins of stereocontrol in asymmetric Pd-catalyzed α-hydroxylation of 1,3-ketoesters
Smith, Alexander M. R.,Rzepa, Henry S.,White, Andrew J. P.,Billen, Denis,Hii, King Kuok
supporting information; experimental part, p. 3085 - 3096 (2010/07/17)
Systematic studies of reaction conditions and subsequent optimization led to the identification of important parameters for stereoselectivity in the asymmetric α-hydroxylation reaction of 1,3-ketoesters. Enantioselectivities of up to 98% can be achieved for cyclic substrates and 88% for acyclic ketoesters. Subsequently, the combination of cyclic/acyclic ketoester, catalyst, and oxidant was found to have a profound effect on reaction rates and turnover-limiting steps. The stereochemistry of the reaction contradicts that observed for other similar electrophilic substitution reactions. This was rationalized by transition-state modeling, which revealed a number of cooperative weak interactions between oxidant, ligand, and counterion, together with C-H/π interactions that cumulatively account for the unusual stereoselectivity.
Palladium-catalyzed carbonylation/acyl migratory insertion sequence
Zhang, Zhenhua,Liu, Yiyang,Gong, Mingxing,Zhao, Xiaokun,Zhang, Yan,Wang, Jianbo
scheme or table, p. 1139 - 1142 (2010/05/02)
Chemical Equation Presented On the move: A palladium-catalyzed reaction of aryl iodides, diazo compounds or N-tosylhyd razones, and carbon monoxide affords β-oxo esters or ketones/ enones (see scheme; DCE = l,2-dichloroethane). The products are delivered with high efficiency through the title sequence.
NaOH-catalyzed crossed Claisen condensation between ketene silyl acetals and methyl esters
Iida, Akira,Takai, Kenta,Okabayashi, Tomohito,Misaki, Tomonori,Tanabe, Yoo
, p. 3171 - 3173 (2008/02/12)
We have developed a practical crossed Claisen condensation between ketene silyl acetals and methyl esters using catalytic NaOH to obtain α-monoalkylated β-keto esters and inacces-sible α,α- dialkylated β-keto esters. The Royal Society of Chemistry 2005.
Stereoselective reduction of 2-methyl-3-oxo esters (or amides) with sodium borohydride catalyzed by manganese (II) chloride or tetrabutylammonium borohydride. A practical preparation of erythro and threo-3-hydroxy-2-methyl esters (or amides)
Taniguchi, Masahiko,Fujii, Hideaki,Oshima, Koichiro,Utimoto, Kiitiro
, p. 11169 - 11182 (2007/10/02)
erythro-3-Hydroxy-2-methylpropionates or erythro-3-hydroxy-2-methylpropionamides were prepared with high stereoselectivity by NaBH4 reduction of the corresponding 2-methyl-3-oxo esters or 2-methyl-3-oxo amides in the presence of a catalytic amount of manganese(II) chloride. On the other hand, reduction of these substrates with n-Bu4NBH4 provided threo-isomers selectively. erythro-Selective reduction of 2-methyl-3-oxo amides with NaBH3CN in 1N HCl-MeOH is also described.
