Article
Chemistry, Physical
Xue-Song Gu, Ying Xiong, Fan Yang, Na Yu, Pu-Cha Yan, Jian-Hua Xie, Qi-Lin Zhou
Summary: An iridium-catalyzed asymmetric hydrogenation method involving dynamic kinetic resolution was successfully developed using chiral spiro PNN-ligands containing a C5-substituted chiral oxazoline unit. This protocol, combined with simple dehydration, provides a straightforward approach to prepare enantiomerically enriched 3-aryloxy tetrahydrofurans, which are prevalent structural motifs in many approved drugs and clinical candidates.
Article
Chemistry, Multidisciplinary
Lu Qian, Xixia Tang, Yulei Wang, Guixia Liu, Zheng Huang
Summary: The use of a chiral (NCP)Ir complex as the precatalyst allows for the asymmetric transfer hydrogenation of diaryl ketones. This method is applicable to various ortho-substituted diaryl ketones and can be conducted in gram scale under mild reaction conditions.
CHINESE JOURNAL OF CHEMISTRY
(2022)
Article
Multidisciplinary Sciences
Congcong Yin, Ya-Fei Jiang, Fanping Huang, Cong-Qiao Xu, Yingmin Pan, Shuang Gao, Gen-Qiang Chen, Xiaobing Ding, Shao-Tao Bai, Qiwei Lang, Jun Li, Xumu Zhang
Summary: In this paper, an efficient anionic Ir catalyst for asymmetric hydrogenation of ketones is reported, which exhibits biocatalysis-like efficacy with high enantiomeric excess and turnover number. In industrial applications, this catalyst plays a significant role in a highly selective process route.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Wei Zhao, Wenji Wang, Huan Zhou, Qishan Liu, Zhiqing Ma, Haizhou Huang, Mingxin Chang
Summary: A one-pot asymmetric hydrogenation of pyridines with subsequent N-alkylation using a traceless Bronsted acid activation strategy is reported. The reaction exhibits high stereoselectivity and can be used to synthesize indolizidines and quinolizidines. Experimental and theoretical studies reveal that chloride anion and noncovalent interactions play important roles in determining the stereoselectivity of the reaction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Zhi Yang, Yu Chen, Linxi Wan, Yuxiao Li, Dan Chen, Jianlin Tao, Pei Tang, Fen-Er Chen
Summary: A highly enantioselective method for the complete hydrogenation of pyrimidinium salts using Ir/(S,S)-f-Binaphane complex as the catalyst was developed. This method provides easy access to fully saturated chiral hexahydropyrimidines, which are prevalent in many bioactive molecules. The reactions exhibit high yields and enantioselectivities under mild reaction conditions without additives. Successful application of this methodology in a continuous flow fashion further extends its practical utility.
Article
Chemistry, Applied
Yin-Feng Ma, Chuan-Jin Hou, De-Quan Wei, Xinwei He, Ting-Ting Chu, Xiu-shuai Chen, Xiang-Ping Hu
Summary: The asymmetric hydrogenation of beta-ketophosphonates with chiral Ir/P,N,N-ligands catalyst leads to high yields of beta-hydroxyphosphonates with good or excellent enantioselectivities under mild conditions.
APPLIED ORGANOMETALLIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Bram B. C. Peters, Norman Birke, Luca Massaro, Pher G. Andersson
Summary: The catalytic asymmetric hydrogenation of olefins is a powerful method for synthesizing chiral compounds. By using an iridium N,P-complex catalyst, various prochiral unsaturated amides can be efficiently reduced with high enantioselectivities. The attractive features of this method include its application in the synthesis of fenpropidin and the potential use of isomeric mixtures as starting materials.
Article
Chemistry, Organic
Victor Garcia-Vazquez, Pablo Martinez-Pardo, Alexandru Postole, A. Ken Inge, Belen Martin-Matute
Summary: This study developed a method for synthesizing chiral trifluoromethylated aliphatic amines, which involves organocatalytic isomerization and imine/enamine reduction to obtain compounds with two noncontiguous stereogenic centers in high yields and selectivities. The method is effective for primary amine substrates and provides a new pathway for synthesizing chiral trifluoromethylated scaffolds.
Article
Chemistry, Organic
Congcong Yin, Yingmin Pan, Longsheng Zheng, Bijin Lin, Jialin Wen, Xumu Zhang
Summary: Enantioselective hydrogenation of imines via an outer-sphere mechanism was achieved using an iridium tridentate catalyst, resulting in high enantioselectivities and turnover numbers up to 10,000. This method was successfully applied in the synthesis of chiral amines with an alpha-stereocenter, allowing for the preparation of cinacalcet with remarkably high enantioselectivity.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Physical
Chao-Wei Zhang, Xian-Qi Hu, Yuan-Hao Dai, Peng Yin, Chuanyong Wang, Wei-Liang Duan
Summary: The catalytic synthesis of P- and axially chiral biaryl phosphine oxides was achieved using Cp*Ir-catalyzed asymmetric C-H coupling, with the stereoselectivity controlled by chiral carboxylic amides. The transformation of products into chiral trivalent phosphine ligands was also demonstrated.
Article
Chemistry, Physical
Huimin Qi, Lixian Wang, Qiangsheng Sun, Wei Sun
Summary: This article describes a stable iridium catalyst with a chiral 2-pyridyl imidazoline ligand for the asymmetric transfer hydrogenation (ATH) of quinolines and N-heteroaryl compounds. The ATH system uses formic acid as the hydrogen source and water as the solvent. Various quinolines and N-heteroaryl compounds can be efficiently converted into desired products with moderate to good enantioselectivity at a catalyst loading as low as 0.001 mol% under mild conditions.
MOLECULAR CATALYSIS
(2022)
Article
Chemistry, Physical
Rachael M. Gitnes, Maggie Wang, Ying Bao, Margaret L. Scheuermann
Summary: Pincer complexes used as precatalysts for organic transformations may form nanoparticles under catalytic conditions, affecting the observed catalytic activity.
Article
Chemistry, Applied
Pinke Yu, Danyi Chen, Yiwen Liu, Congcong Yin, Qixing Liu, Haifeng Zhou
Summary: An asymmetric transfer hydrogenation of 2-oxazolones using a chiral diamine ruthenium catalyst, potassium formate as a hydrogen source, potassium carbonate as an additive in 2,2,2-trifluoroethanol has been described. The reaction yielded a series of chiral 2-oxazolidinones with 29%-95% yields and 86%->99% ee's. Gram-scale synthesis and downstream derivatizations of chiral 2-oxazolidinone demonstrate the practicality of this method.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Organic
Jun Yan, Yu Nie, Feng Gao, Qianjia Yuan, Fang Xie, Wanbin Zhang
Summary: An efficient synthesis of chiral 3-arylindanones was achieved through iridium-catalyzed asymmetric hydrogenation, showing good compatibility with various functional groups and delivering high yields with good enantioselectivities. The reaction was performed on a gram-scale with quantitative yield and the products were easily derivatized into natural products and pharmaceutical agents.
Article
Chemistry, Multidisciplinary
Pep Rojo, Medea Molinari, Albert Cabre, Clara Garcia-Mateos, Antoni Riera, Xavier Verdaguer
Summary: Chiral compounds containing nitrogen heteroatoms are crucial for the chemical, pharmaceutical, and agrochemical industries. In this study, a series of P-stereogenic phosphinooxazoline iridium catalysts were synthesized and successfully used in the asymmetric hydrogenation of N-Boc-2,3-diarylallyl amines, achieving high enantioselectivity. The synthetic utility of the obtained 2,3-diarylpropyl amines was also demonstrated.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Polymer Science
Haruki Nagae, Shin-ya Akebi, Saki Matsushiro, Kazutaka Sakamoto, Takanori Iwasaki, Kyoko Nozaki, Kazushi Mashima
Summary: Active methylene compounds, such as nitrile compounds and carbonyl compounds, can act as chain transfer agents in the alternating copolymerization of CO2 and cyclohexene oxide to produce end-functionalized polycarbonates with narrow molecular weight distribution and high carbonate linkage. Acidic nitrile compounds can also result in double chain propagation to form telechelic polycarbonate diols.
Article
Chemistry, Multidisciplinary
Kohei Nishi, Hayato Tsurugi, Kazushi Mashima
Summary: Chromium-catalyzed olefination of aryl aldehydes with haloforms using 2,3,5,6-tetramethyl-N,N'-bis(trimethylsilyl)-1,4-dihydropyrazine (1a) as an organic reducing agent leads to trans-selective formation of beta-halostyrene derivatives. This reaction eliminates the need for metal powders such as zinc and manganese as reductants, reducing metal-based reaction waste.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Organic
Yohei Ueda, Hayato Tsurugi, Kazushi Mashima
Summary: Cobalt-catalyzed hydroalkynylation of alkynes, alkenes, and imines allows for the synthesis of internal alkynes with various functional groups adjacent to the carbon-carbon triple bond in an atom-economical manner. In addition, cross-coupling reactions using alkynylcobalt species generated in situ from terminal alkynes, haloalkynes, and metal acetylides selectively provide internal aryl and alkylalkynes.
Article
Chemistry, Physical
Kosuke Higashida, Valentin Smail, Haruki Nagae, Jean-Francois Carpentier, Kazushi Mashima
Summary: We successfully achieved nickel(0)-catalyzed asymmetric allylic alkylation (AAA) of beta-dicarbonyl compounds under ambient conditions by activating unstrained C-C bonds of 2-allylated 2-methylcyclohexane-1,3-dione derivatives. The reaction produced quaternary chiral compounds with high yield and enantioselectivity. The mechanism of the AAA reaction with the Ni(0)-(S)-tol-MeO-BIPHEP catalyst system was elucidated through control experiments and DFT calculations.
Article
Chemistry, Organic
Emna Mejri, Kosuke Higashida, Yuta Kondo, Anna Nawachi, Hiroyuki Morimoto, Takashi Ohshima, Masaya Sawamura, Yohei Shimizu
Summary: A photoinduced N-internal vicinal aminochlorination reaction of styrene-type terminal alkenes was developed. The reaction proceeded without any catalyst, and the use of N-chloro(fluorenoneimine) as both a photoactivatable aminating agent and a chlorinating agent was essential. The introduced imine moiety at the internal position of the alkenes could be hydrolyzed under mild conditions to provide versatile beta-chlorinated primary amines, which demonstrated synthetic utility in several transformations.
Article
Chemistry, Physical
Kohei Nishi, Hayato Tsurugi, Kazushi Mashima
Summary: Chromium(III) trichloride combined with aryl/alkyl Grignard reagents showed high catalytic activity for the synthesis of syn-2-aryl/alkyl-1,2-dihydronaphthalen-1-ols through the ring-opening aryl/alkylation of 7-oxabenzonorbornadiene derivatives. The chromium catalyst allowed the use of unstable aryl Grignard reagents with esters and N-protecting groups. In situ formed diarylchromate(I) from tetraarylchromate(III) was identified as the active species in this catalytic reaction based on control experiments.
Article
Chemistry, Multidisciplinary
Akito Kitabayashi, Yuriko Ono, Tetsuya Taketsugu, Masaya Sawamura, Kosuke Higashida
Summary: As a dimetal-binding rigid scaffold, 2-(pyridin-2-yl)imidazo[1,5-b]pyridazine-7-ylidene was introduced. The scaffold was converted into an Au,N,N-tridentate ligand through binding of a Au(I)Cl moiety at the carbene center. Trinuclear heterobimetallic complexes were synthesized with different 3d-metal sources, and metallophilic interactions were investigated using quantum chemical calculations.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Miyu Sato, Vishal Kumar Rawat, Kosuke Higashida, Masaya Sawamura
Summary: In this study, a seven-exo-dig hydrocarboxylation of nonactivated internal alkynes was achieved using cooperative gold-zinc catalysts with a conformationally flexible linker chains. The high catalytic activity was attributed to the proximity effect between the gold and zinc sites, where the cationic gold species activated the internal alkyne and the carboxylic acid was deprotonated by the basic zinc site. The introduction of a bulky aromatic N-substituent in the NHC ligand facilitated seven-membered ring formation and minimized intermolecular hydrocarboxylation as an undesired side reaction. The reaction mechanism was investigated using quantum chemical calculations.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Yusuke Masuda, Daichi Ikeshita, Kosuke Higashida, Masaki Yoshida, Naoki Ishida, Masahiro Murakami, Masaya Sawamura
Summary: Under photocatalytic conditions, tri(t-butyl)phosphine and terminal alkynes undergo 1,2-phosphorus-migrative [3 + 2] cycloaddition in the presence of a proton source. The reaction shows broad functional group tolerance and yields substituted cyclic phosphonium salts that can be further derivatized by Wittig olefination. Theoretical studies suggest that the phosphorus 1,2-migration of a β-phosphonioalkyl radical proceeds through a phosphine radical cation-alkene complex as a pseudointermediate, with the two fragments in the intermediate bound to each other through multiple noncovalent interactions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Haruki Nagae, Saki Matsushiro, Jun Okuda, Kazushi Mashima
Summary: We discovered that a cationic hetero tetranuclear complex with a calcium and three cobalt ions demonstrated high catalytic activity for the alternating copolymerization of propylene oxide (PO) and carbon dioxide (CO2). The tertiary anilinium salt [PhNMe2H][B(C6F5)(4)] was identified as the best additive to generate the cationic species and maintain polymer selectivity and carbonate linkage, even at 1.0 MPa CO2. Density functional theory calculations revealed that the reaction pathway mediated by the cationic complex is more favorable than that mediated by the neutral complex, with an energy difference of 1.0 kcal mol(-1). Additionally, we found that the exchange of flexible ligands between calcium and cobalt ions is crucial for the smooth proceeding of the alternating copolymerization.
Article
Chemistry, Physical
Kohei Nishi, Hayato Tsurugi, Kazushi Mashima
Summary: Chromium(III) trichloride in combination with aryl/alkyl Grignard reagents exhibited high catalytic activity for the ring-opening arylation reaction of 7-oxabenzonorbornadiene derivatives, producing syn-2-aryl/alkyl-1,2-dihydronaphthalen-1-ols in high yields. The superior catalytic activity of the chromium catalyst allowed the use of unstable aryl Grignard reagents. Control experiments suggested that the in situ formed diarylchromate(I) served as the active species in the catalytic reaction.
Article
Chemistry, Physical
Kosuke Higashida, Valentin Smail, Haruki Nagae, Jean-Francois Carpentier, Kazushi Mashima
Summary: We achieved a nickel(0)-catalyzed asymmetric allylic alkylation reaction of beta-dicarbonyl compounds under ambient conditions, resulting in high yields of quaternary chiral compounds with high enantioselectivity.
