16460-78-9Relevant academic research and scientific papers
Asymmetric conjugate addition to alkylidene malonates
Alexakis, Alexandre,Benhaim, Cyril
, p. 1151 - 1157 (2001)
Dialkylzinc and trialkylaluminium reagents undergo conjugate addition to alkylidene malonates with 0.5% copper triflate as catalyst. The reaction could be made enantioselective by completing the reaction in the presence of 0.5-1.0 mol% of chiral phosphorus ligand. Enantiomeric excesses (e.e.s) of up to 73% could be attained with a ligand prepared from TADDOL and 2-naphthylcyclohexanol.
Enantioselective intermolecular free radical conjugate additions. Application of a pyrazole template
Sibi, Mukund P.,Shay, John J.,Ji, Jianguo
, p. 5955 - 5958 (1997)
An achiral pyrazole template has been evaluated in enantioselective conjugate radical additions. The enantioselectivity using the pyrazole template is inferior to those obtained from an oxazolidinone template. The two templates give products of opposite c
Asymmetric Alkylation of a Chiral α-Amino Alkenenitrile
Fang, Jim-Min,Chang, Chih-Jung
, p. 1787 - 1788 (1989)
Alkylation of the unsymmetric allylic anion generated from 2-(L-ephedrino)-4-phenylbut-3-enenitrile occurred exclusively at C-4 to give predominantly products having the 4R-configuration ; the stereoselectivity increased remarkably when the reaction was conducted in a mixture of hexamethylphosphoramide and lithium iodide.
An efficient synthetic route to chiral 4-alkyl-1,2,3,4-tetrahydroquinolines: Enantioselective synthesis of (R)-4-ethyl-1,2,3,4-tetrahydroquinoline
Mani, Neelakandha S.,Wu, Min
, p. 4687 - 4691 (2000)
An efficient synthetic route to non-racemic chiral 4-alkyl-1,2,3,4-tetrahydroquinoline is described. (4R)-4-Ethyl-1,2,3,4-tetrahydroquinoline was obtained by the organoaluminum promoted modified Beckmann rearrangement involving the oxime sulfonate of (3R)
Asymmetric Conjugate Addition of Grignard Reagents in the Presence of Tertiary Amines to α,β-Unsaturated Amides Derived from (S)-2-(1-Hydroxy-1-methylethyl)pyrrolidine or (S)-Prolinol
Soai, Kenso,Machida, Hideaki,Ookawa, Atsuhiro
, p. 469 - 470 (1985)
In the presence of tertiary amines, diastereoselective conjugate addition of Grignard reagents to α,β-unsaturated amides affords 3-substituted carboxylic acids of high enantiomeric excess (up to 89percent e.e.).
Ruthenium-catalyzed intramolecular arene C(sp2)-H amidation for synthesis of 3,4-dihydroquinolin-2(1 H)-ones
Au, Chi-Ming,Ling, Cho-Hon,Sun, Wenlong,Yu, Wing-Yiu
supporting information, p. 3310 - 3314 (2021/05/29)
We report the [Ru(p-cymene)(l-proline)Cl] ([Ru1])-catalyzed cyclization of 1,4,2-dioxazol-5-ones to form dihydroquinoline-2-ones in excellent yields with excellent regioselectivity via a formal intramolecular arene C(sp2)-H amidation. The reactions of the 2- and 4-substituted aryl dioxazolones proceeds initially through spirolactamization via electrophilic amidation at the arene site, which is para or ortho to the substituent. A Hammett correlation study showed that the spirolactamization is likely to occur by electrophilic nitrenoid attack at the arene, which is characterized by a negative ρ value of -0.73.
Construction of enantioenriched 9H-Fluorene frameworks via a cascade reaction involving remote vinylogous dynamic kinetic resolution
Hu, Cui-Xia,Chen, Lin,Hu, Di,Song, Xue,Chen, Zhi-Chao,Du, Wei,Chen, Ying-Chun
supporting information, p. 8973 - 8977 (2020/11/30)
The benzylic C-H group of α,α-dicyanoolefins from 3-substituted 1-indanones could be significantly activated via transmission along the aromatic system, thus enabling dynamic kinetic resolution via a traditional reversible deprotonation- protonation process. Enantioenriched 9-substituted 9H-fluorene frameworks were finally constructed through an asymmetric vinylogous Michael addition to nitroolefins, followed by a cascade cyclization and oxidative aromatization process, under the catalysis of a chiral bifunctional thiourea-tertiary amine.
Identification of an Esterase Isolated Using Metagenomic Technology which Displays an Unusual Substrate Scope and its Characterisation as an Enantioselective Biocatalyst
Gavin, Declan P.,Murphy, Edel J.,Foley, Aoife M.,Castilla, Ignacio Abreu,Reen, F. Jerry,Woods, David F.,Collins, Stuart G.,O'Gara, Fergal,Maguire, Anita R.
, p. 2466 - 2474 (2019/03/11)
Evaluation of an esterase annotated as 26D isolated from a marine metagenomic library is described. Esterase 26D was found to have a unique substrate scope, including synthetic transformations which could not be readily effected in a synthetically useful manner using commercially available enzymes. Esterase 26D was more selective towards substrates which had larger, more sterically demanding substituents (i. e. iso-propyl or tert-butyl groups) on the β-carbon, which is in contrast to previously tested commercially available enzymes which displayed a preference for substrates with sterically less demanding substituents (e.g. methyl group) at the β-carbon. (Figure presented.).
Enantioselective Hydrogenation of β,β-Disubstituted Unsaturated Carboxylic Acids under Base-Free Conditions
Yan, Qiaozhi,Kong, Duanyang,Zhao, Wei,Zi, Guofu,Hou, Guohua
, p. 2070 - 2077 (2016/03/15)
An additive-free enantioselective hydrogenation of β,β-disubstituted unsaturated carboxylic acids catalyzed by the Rh-(R,R)-f-spiroPhos complex has been developed. Under mild conditions, a wide scope of β,β-disubstituted unsaturated carboxylic acids were hydrogenated to the corresponding chiral carboxylic acids with excellent enantioselectivities (up to 99.3% ee). This methodology was also successfully applied to the synthesis of the pharmaceutical molecule indatraline.
Trialkyl Methanetricarboxylate as Dialkyl Malonate Surrogate in Copper-Catalyzed Enantioselective Propargylic Substitution
Huang, Guanxin,Cheng, Cang,Ge, Luo,Guo, Beibei,Zhao, Long,Wu, Xiaoyu
supporting information, p. 4894 - 4897 (2015/10/12)
The first copper-catalyzed enantioselective propargylation of trialkyl methantricarboxylate with propargylic alcohol derivatives was developed. The tricarboxylate unit in the obtained adducts could be easily transformed into a malonate moiety by treating with in situ generated NaOEt in excellent yield without racemization.
