13448-81-2Relevant academic research and scientific papers
Isothiourea-Catalyzed Acylative Kinetic Resolution of Tertiary α-Hydroxy Esters
Greenhalgh, Mark D.,Laina-Martín, Víctor,Neyyappadath, Rifahath M.,Qu, Shen,Smith, Andrew D.,Smith, Samuel M.
, p. 16572 - 16578 (2020/09/09)
A highly enantioselective isothiourea-catalyzed acylative kinetic resolution (KR) of acyclic tertiary alcohols has been developed. Selectivity factors of up to 200 were achieved for the KR of tertiary alcohols bearing an adjacent ester substituent, with both reaction conversion and enantioselectivity found to be sensitive to the steric and electronic environment at the stereogenic tertiary carbinol centre. For more sterically congested alcohols, the use of a recently-developed isoselenourea catalyst was optimal, with equivalent enantioselectivity but higher conversion achieved in comparison to the isothiourea HyperBTM. Diastereomeric acylation transition state models are proposed to rationalize the origins of enantiodiscrimination in this process. This KR procedure was also translated to a continuous-flow process using a polymer-supported variant of the catalyst.
Solvent-induced chirality switching in the enantioseparation of regioisomeric hydroxyphenylpropionic acids via diastereomeric salt formation with (1R,2S)-2-amino-1,2-diphenylethanol
Kodama, Koichi,Nagata, Jun,Kurozumi, Nobuhiro,Shitara, Hiroaki,Hirose, Takuji
, p. 460 - 466 (2017/03/23)
The enantioseparation of three hydroxyphenylpropionic acid isomers via diastereomeric salt formation with (1R,2S)-2-amino-1,2-diphenylethanol has been demonstrated. The racemates of all three acid isomers were successfully separated with high efficiency (0.56–0.84) after single crystallization. For 2-hydroxy-3-phenylpropionic acid 4, the configuration of the less-soluble salt was controlled by the crystallization solvent: the (R)-4 salt was crystallized from water, while 2-propanol afforded the (S)-4 salt. The chiral recognition mechanism of the three acids was discussed based on the crystal structures of the diastereomeric salts.
Enantioselective addition of organozinc reagents to carbonyl compounds catalyzed by a camphor derived chiral γ-amino thiol ligand
Wu, Hsyueh-Liang,Wu, Ping-Yu,Cheng, Ying-Ni,Uang, Biing-Jiun
, p. 2656 - 2665 (2016/05/10)
In this article, the design and synthesis of the chiral camphor derived γ-amino thiol ligand 17 and its application in catalytic enantioselective carbon-carbon forming reactions through the addition of organozinc reagents to carbonyl compounds is described. The catalytic activity and enantioselectivity of ligand 17 is demonstrated in the enantioselective addition of various organozinc reagents to aldehydes and ketoesters, offering the corresponding alcohols in high yields and enantioselectivities. The role of the mercapto group in the highly enantioselective 1,2-addition reaction of organozincs to aldehyde is also discussed.
Enantioselective fluorination of α-branched aldehydes and subsequent conversion to α-hydroxyacetals via stereospecific C-F bond cleavage
Shibatomi, Kazutaka,Kitahara, Kazumasa,Okimi, Takuya,Abe, Yoshiyuki,Iwasa, Seiji
, p. 1388 - 1392 (2016/02/05)
The highly enantioselective fluorination of α-branched aldehydes was achieved using newly developed chiral primary amine catalyst 1. Furthermore, the C-F bond cleavage of the resulting α-fluoroaldehydes proceeded smoothly under alcoholic alkaline conditio
Asymmetric Ti-crossed Claisen condensation: Application to concise asymmetric total synthesis of alternaric acid
Nagase, Ryohei,Oguni, Yumiko,Ureshino, Satoko,Mura, Hiroaki,Misaki, Tomonori,Tanabe, Yoo
, p. 7001 - 7003 (2013/09/02)
Asymmetric Ti-crossed Claisen condensation utilizing the dioxane-2,5-dione chiral template and its successful application to total synthesis of chiral alternaric acid are described.
Highly homogeneous stereocontrolled construction of quaternary hydroxyesters by addition of dimethylzinc to α-ketoesters promoted by chiral perhydrobenzoxazines and B(OEt)3
Infante, Rebeca,Nieto, Javier,Andres, Celia
scheme or table, p. 4375 - 4379 (2012/05/20)
A highly efficient enantioselective addition of Me2Zn to α-ketoesters, assisted by a chiral perhydro-1,3-benzoxazine ligand, is described. This novel catalytic system offers homogeneous elevated enantioselectivities in the preparation of α-hydroxyesters that bear a quaternary stereocenter, with a minor dependence on electronic and steric effects when aromatic, heteroaromatic, or aliphatic α-ketoesters are employed. The catalyst can be recovered and reused without loss of activity.
Enantioselective alkynylation of carbonyl compounds with trimethoxysilylalkynes catalyzed by lithium binaphtholate
Ueda, Tomohiro,Tanaka, Kana,Ichibakase, Tomonori,Orito, Yuya,Nakajima, Makoto
experimental part, p. 7726 - 7731 (2010/10/21)
Enantioselective alkynylation of aldehydes and ketones was accomplished using trimethoxysilylalkynes as alkynylating reagents and lithium 3,3′-diphenylbinaphtholate as a catalyst. Optically active propargylic alcohols were obtained in good to high chemica
A new type of oxidation-reduction condensation by the combined use of phenyl diphenylphosphinite and oxidant
Mukaiyama, Teruaki,Kuroda, Kiichi,Maruyama, Yuji
scheme or table, p. 63 - 82 (2010/04/23)
A new type of oxidation-reduction condensation of alcohols with sulfur, nitrogen, and oxygen nucleophiles by the combined use of phenyl diphenylphosphinite (PhOPPh2) and oxidants such as azides or diethyl azodicarboxylate (DEAD) are described. In these reactions, chiral secondary and tertiary alcohols are converted into the corresponding chiral sulfides, azides, esters and ethers under mild and neutral conditions with almost complete inversion of stereochemical configuration.
Enantioselective synthesis of quaternary stereogenic centers through catalytic asymmetric addition of dimethylzinc to α-ketoesters with chiral cis-cyclopropane-based amide alcohol as ligand
Zheng, Bing,Hou, Shicong,Li, Zhiyuan,Guo, Hongchao,Zhong, Jiangchun,Wang, Min
experimental part, p. 2125 - 2129 (2010/03/01)
A new amino alcohol with a chiral cyclopropane backbone has been developed and used in the catalytic asymmetric diethylzinc addition to various types of α-ketoesters. This cyclopropane-based chiral amino alcohol shows moderate enantioselectivity in the ad
