24867-90-1Relevant academic research and scientific papers
New chiral ligands for catalytic asymmetric transfer hydrogenation of ketones
Jiang, Yutong,Jiang, Qiongzhong,Zhu, Guoxin,Zhang, Xumu
, p. 6565 - 6568 (1997)
New chiral ligands 3 and 5 have been synthesized. Their Ru(II) complexes are effective catalysts for transfer hydrogenation of both aryl allyl and dialkyl ketones (with ee's up to 79.5%).
Manganese(I)-Catalyzed H-P Bond Activation via Metal-Ligand Cooperation
Pérez, Juana M.,Postolache, Roxana,Casti?eira Reis, Marta,Sinnema, Esther G.,Vargová, Denisa,De Vries, Folkert,Otten, Edwin,Ge, Luo,Harutyunyan, Syuzanna R.
supporting information, p. 20071 - 20076 (2021/12/03)
Here we report that chiral Mn(I) complexes are capable of H-P bond activation. This activation mode enables a general method for the hydrophosphination of internal and terminal α,β-unsaturated nitriles. Metal-ligand cooperation, a strategy previously not considered for catalytic H-P bond activation, is at the base of the mechanistic action of the Mn(I)-based catalyst. Our computational studies support a stepwise mechanism for the hydrophosphination and provide insight into the origin of the enantioselectivity.
PQXdpap: Helical Poly(quinoxaline-2,3-diyl)s Bearing 4-(Dipropylamino)pyridin-3-yl Pendants as Chirality-Switchable Nucleophilic Catalysts for the Kinetic Resolution of Secondary Alcohols
Murakami, Ryo,Suginome, Michinori,Yamamoto, Takeshi
supporting information, p. 8711 - 8716 (2021/11/24)
Helically chiral poly(quinoxaline-2,3-diyl)s bearing 4-(dipropylamino)pyridin-3-yl pendants at the 5-position of the quinoxaline ring (PQXdpap) exhibited high catalytic activities and moderate to high selectivities (up to s = 87) in the acylative kinetic resolution of secondary alcohols. The solvent-dependent helical chirality switching of PQXdpap between pure toluene and a 1:1 mixture of toluene and 1,1,2-trichloroethane enabled the preparation of either compound of a pair of enantiomerically pure alcohols (>99% ee) from a single catalyst.
Chiral phosphoric acid catalyzed asymmetric transfer hydrogenation of bulky aryl ketones with ammonia borane
Zhou, Qiwen,Meng, Wei,Feng, Xiangqing,Du, Haifeng,Yang, Jing
supporting information, (2019/11/28)
An asymmetric transfer hydrogenation of bulky aryl ketones with ammonia borane was successfully realized with chiral phosphoric acid (CPA) as catalyst and water as additive. A variety of optically active secondary alcohols were obtained in good to high yi
Direct Asymmetric Hydrogenation and Dynamic Kinetic Resolution of Aryl Ketones Catalyzed by an Iridium-NHC Exhibiting High Enantio- and Diastereoselectivity
Ayya Swamy P, Chinna,Varenikov, Andrii,de Ruiter, Graham
supporting information, p. 2333 - 2337 (2020/02/11)
A chiral iridium carbene-oxazoline catalyst is reported that is able to directly and efficiently hydrogenate a wide variety of ketones in excellent yields and good enantioselectivity (up to 93 % ee). Moreover, when using racemic α-substituted ketones, excellent diastereoselectivities were obtained (dr 99:1) by dynamic kinetic resolution of the in situ formed enolate. Overall, the herein described hydrogenation occurs under ambient conditions using low hydrogen pressures, providing a direct and atom efficient method towards chiral secondary alcohols.
Manganese-Catalyzed Enantioselective Hydrogenation of Simple Ketones Using an Imidazole-Based Chiral PNN Tridentate Ligand
Chen, Jiachen,Hou, Huacui,Ling, Fei,Nian, Sanfei,Wu, Feifei,Xu, Min,Yi, Xiao,Zhong, Weihui
supporting information, p. 285 - 289 (2020/02/18)
A series of Mn(I) catalysts containing imidazole-based chiral PNN tridentate ligands with controllable 'side arm' groups have been established, enabling the inexpensive base-promoted asymmetric hydrogenation of simple ketones with outstanding activities (up to 8200 TON) and good enantioselectivities (up to 88.5percent ee). This protocol features wide substrate scope and functional group tolerance, thereby providing easy access to a key intermediate of crizotinib.
Enantioselective Hydroboration of Ketones Catalyzed by Rare-Earth Metal Complexes Containing Trost Ligands
Lu, Chengrong,Sun, Yuli,Xue, Mingqiang,Zhao, Bei
, p. 10504 - 10513 (2020/09/23)
Four chiral dinuclear rare-earth metal complexes [REL1]2 (RE = Y(1), Eu(2), Nd(3), La (4)) stabilized by Trost proligand H3L1 (H3L1 = (S,S)-2,6-bis[2-(hydroxydiphenylmethyl)pyrrolidin-1-ylmethyl]-4-methylphenol) were first prepared, and all were characterized by X-ray diffraction. Complex 4 was employed as the catalyst for enantioselective hydroboration reaction of substituted ketones, and the corresponding secondary alcohols with excellent yields and high ee values were obtained using reductant HBpin. The same result was also achieved using the combination of lanthanium amides La[N(SiMe3)2]3 with Trost proligand H3L1 in a 1:1 molar ratio. The experimental findings and DFT calculation revealed the possible mechanism of the enantioselective hydroboration reaction and defined the origin of the enantioselectivity in the current system.
P-chirogenic Trost ligands mediated asymmetric hydrogenation of simple ketones
Du, Peng,Liu, Yan-Lan,Lu, Xiao-Bing
supporting information, (2020/09/22)
Herein, we report a highly active catalyst system consisting of (Rc,Rc,Rp,Rp)-P-chirogenic Trost ligand and [Ru(C6H6)Cl2]2 for asymmetric hydrogenation of simple ketones, affording the corresponding optically active alcohols in moderate enantioselectivity. A synergetic effect between P- and C-chirogenic centers of the P-chirogenic Trost ligands was observed in this asymmetric hydrogenation process.
Iridium-Catalyzed Enantioselective Transfer Hydrogenation of Ketones Controlled by Alcohol Hydrogen-Bonding and sp3-C?H Noncovalent Interactions
Murayama, Hiroaki,Heike, Yoshito,Higashida, Kosuke,Shimizu, Yohei,Yodsin, Nuttapon,Wongnongwa, Yutthana,Jungsuttiwong, Siriporn,Mori, Seiji,Sawamura, Masaya
supporting information, p. 4655 - 4661 (2020/07/13)
Iridium-catalyzed enantioselective transfer hydrogenation of ketones with formic acid was developed using a prolinol-phosphine chiral ligand. Cooperative action of the iridium atom and the ligand through alcohol-alkoxide interconversion is crucial to facilitate the transfer hydrogenation. Various ketones including alkyl aryl ketones, ketoesters, and an aryl heteroaryl ketone were competent substrates. An attractive feature of this catalysis is efficient discrimination between the alkyl and aryl substituents of the ketones, promoting hydrogenation with the identical sense of enantioselection regardless of steric demand of the alkyl substituent and thus resulting in a rare case of highly enantioselective transfer hydrogenation of tert-alkyl aryl ketones. Quantum chemical calculations revealed that the sp3-C?H/π interaction between an sp3-C?H bond of the prolinol-phosphine ligand and the aryl substituent of the ketone is crucial for the enantioselection in combination with O?H???O/sp3-C?H???O two-point hydrogen-bonding between the chiral ligand and carbonyl group. (Figure presented.).
Versatile and Enantioselective Preparation of Planar-Chiral Metallocene-Fused 4-Dialkylaminopyridines and Their Application in Asymmetric Organocatalysis
Yoshida, Kazuhiro,Liu, Qiang,Yasue, Risa,Wada, Shiro,Kimura, Ryosuke,Konishi, Takuma,Ogasawara, Masamichi
, p. 292 - 301 (2019/12/24)
A series of ferrocene-fused planar-chiral N-tosyl-4-pyridones (S)-2b-d were prepared in enantiomerically pure forms. Starting with the chiral ferrocenyl acetals, 1-[(2S,4S)-4-methoxymethyl-1,3-dioxan-2-yl]-1′,2′,3′,4′,5′-R5-ferrocenes ((-)-3b,
