36041-80-2Relevant academic research and scientific papers
Application of axially dissymmetric ligand recoverable with fluorous solvent as a chiral auxiliary
Omote, Masaaki,Nishimura, Yuji,Sato, Kazuyuki,Ando, Akira,Kumadaki, Itsumaro
, p. 74 - 78 (2006)
(Ra)-(R)2-2,2′-Bis(1-hydroxy-1H-perfluorooctyl)biphenyl ((Ra)-(R)2-1c), which is an axially dissymmetric ligand with two chiral centers, works as a good chiral auxiliary for asymmetric aldol reaction. Thus, the reaction of monopropan
Copper-Catalyzed Enantioselective Reductive Aldol Reaction of α,β-Unsaturated Carboxylic Acids to Alkyl Aryl Ketones: Silanes as Activator and Transient Protecting Group
Suzuki, Hirotsugu,Yoneoka, Kenji,Kondo, Sora,Matsuda, Takanori
supporting information, (2022/01/26)
The first enantioselective reductive aldol reaction of unprotected α,β-unsaturated carboxylic acids was developed by employing a copper/bisphosphine catalyst. The reaction features in situ protection and activation of an α,β-unsaturated carboxylic acid by a hydrosilane. The copper enolate formed in situ reacts with an alkyl aryl ketone to afford the β-hydroxy carboxylic acid with excellent enantioselectivity (up to 99 % ee). The corresponding gram-scale reaction with a low catalyst loading and the derivatization of the β-hydroxy carboxylic acids highlight the practicality of this transformation.
Fe-Catalyzed Anaerobic Mukaiyama-Type Hydration of Alkenes using Nitroarenes
Bhunia, Anup,Bergander, Klaus,Daniliuc, Constantin Gabriel,Studer, Armido
supporting information, p. 8313 - 8320 (2021/03/08)
Hydration of alkenes using first row transition metals (Fe, Co, Mn) under oxygen atmosphere (Mukaiyama-type hydration) is highly practical for alkene functionalization in complex synthesis. Different hydration protocols have been developed, however, control of the stereoselectivity remains a challenge. Herein, highly diastereoselective Fe-catalyzed anaerobic Markovnikov-selective hydration of alkenes using nitroarenes as oxygenation reagents is reported. The nitro moiety is not well explored in radical chemistry and nitroarenes are known to suppress free radical processes. Our findings show the potential of cheap nitroarenes as oxygen donors in radical transformations. Secondary and tertiary alcohols were prepared with excellent Markovnikov-selectivity. The method features large functional group tolerance and is also applicable for late-stage chemical functionalization. The anaerobic protocol outperforms existing hydration methodology in terms of reaction efficiency and selectivity.
Visible-Light-Driven, Metal-Free Divergent Difunctionalization of Alkenes Using Alkyl Formates
Zheng, Ming,Hou, Jing,Zhan, Le-Wu,Huang, Yan,Chen, Ling,Hua, Li-Li,Li, Yan,Tang, Wan-Ying,Li, Bin-Dong
, p. 542 - 553 (2021/01/14)
In recent decades, difunctionalization of alkenes has received considerable attention as an efficient and straightforward way to increase molecular complexity. However, examples of the difunctionalization of alkenes initiated by the intermolecular addition of alkoxycarbonyl radicals providing substituted alkanoates are still rare. Herein, we present the visible light-driven metal-free divergent difunctionalization of alkenes triggered by the intermolecular addition of alkoxycarbonyl radicals under ambient conditions. Employing alkyl formates as precursors of alkoxycarbonyl radicals and 4CzIPN as the photocatalyst, a variety of substituted alkanoates, including β-alkoxy, β-hydroxy, β-dimethoxymethoxy, and β-formyloxy alkanoates, could be facilely accessed with high functional group tolerance and high efficiency. Moreover, the mechanism study revealed that β-hydroxy alkanoates were generated by a selective decomposition of orthoformates promoted by the N-alkoxyazinium salt.
Manganese-Catalyzed anti-Selective Asymmetric Hydrogenation of α-Substituted β-Ketoamides
Ding, Kuiling,Han, Zhaobin,Wang, Zheng,Zhang, Linli
supporting information, p. 15565 - 15569 (2020/07/06)
A Mn-catalyzed diastereo- and enantioselective hydrogenation of α-substituted β-ketoamides has been realized for the first time under dynamic kinetic resolution conditions. anti-α-Substituted β-hydroxy amides, which are useful building blocks for the synthesis of bioactive molecules and chiral drugs, were prepared in high yields with excellent selectivity (up to >99 percent dr and >99 percent ee) and unprecedentedly high activity (TON up to 10000). The origin of the excellent stereoselectivity was clarified by DFT calculations.
Ni-Catalyzed chemoselective alcoholysis of: N -acyloxazolidinones
Huang, Pei-Qiang,Geng, Hui
supporting information, p. 593 - 599 (2018/02/14)
Although N-acyloxazolidinone-based (catalytic) asymmetric synthetic methodologies occupy an important position in modern organic synthesis, the catalytic cleavage of a chiral auxiliary remains underdeveloped. We report the Ni(cod)2/bipyr.-catalyzed alcoholysis of N-acyloxazolidinones to deliver esters. The reaction is broad in scope for both N-acyloxazolidinone substrates and alcohol nucleophiles, and displays good functional group tolerance and excellent chemoselectivity. A gram-scale methanolysis allowed the enantioselective synthesis of the C22-C26 segment of a close analogue of the potent immunosuppressant agent FK506.
Direct Catalytic Asymmetric Aldol Reaction of α-Alkylamides
Liu, Zijian,Takeuchi, Toshifumi,Pluta, Roman,Arteaga Arteaga, Fernando,Kumagai, Naoya,Shibasaki, Masakatsu
, p. 710 - 713 (2017/02/10)
A catalytic asymmetric aldol reaction directly employing amides as latent enolates has remained elusive because of the resistance of amides to enolization. A direct aldol reaction of α-alkylamides without any electron-withdrawing group harnessed by specif
Stereoselective Construction of Entire Diastereomeric Stereotetrads Based on an Asymmetric Morita–Baylis–Hillman Reaction
Yoshimura, Hikaru,Ishihara, Jun,Hatakeyama, Susumi
, p. 2719 - 2729 (2017/05/29)
A method for the enantio- and diastereoselective construction of all possible stereoisomers of a polypropionate stereotetrad having four contiguous stereogenic centers has been developed. The approach features an iterative sequence of cinchona-alkaloid-ca
Chiral ferrocene P-N-N ligand with high steric hindrance, and preparation method and application thereof
-
Paragraph 0121-0124, (2018/01/13)
The invention provides a chiral ferrocene P-N-N ligand compound with high steric hindrance, and a preparation method and application thereof, specifically application of the chiral ferrocene P-N-N ligand compound to asymmetric catalytic hydrogenation of beta-keto ester compounds. The preparation method for the chiral ferrocene P-N-N ligand compound with high steric hindrance comprises the following steps: dissolving a chiral ferrocenephosphine-amine compound and a pyridone compound in a reaction solvent; adding active Al2O3 and a dehydrating agent; carrying out a reflux condensation reaction; then carrying out re-dissolving in absolute ethyl alcohol after filtering and desolventizing; adding a palladium/carbon catalyst and carrying out a hydrogenation reaction in an autoclave under a certain reaction pressure; and then successively carrying out filtration, desolventizing and column chromatographic treatment so as to obtain the desired chiral ferrocene P-N-N ligand compound with high steric hindrance. The chiral ferrocene P-N-N ligand compound with high steric hindrance in the invention can be used for asymmetric catalytic hydrogenation of beta-keto ester and can realize high-yield, high-diastereoselectivity high-enantioselectivity preparation of chiral beta-hydroxy ester.
Sterically Hindered Chiral Ferrocenyl P,N,N-Ligands for Highly Diastereo-/Enantioselective Ir-Catalyzed Hydrogenation of α-Alkyl-β-ketoesters via Dynamic Kinetic Resolution
Hou, Chuan-Jin,Hu, Xiang-Ping
supporting information, p. 5592 - 5595 (2016/11/17)
A new class of sterically hindered chiral ferrocenyl P,N,N-ligands have been prepared through a two-step transformation from (Sc,Rp)-PPFNH2, in which a new (R)-stereogenic center at the pyridinylmethyl position was generated in high diastereoselectivity. With these newly developed P,N,N-ligands, Ir-catalyzed asymmetric hydrogenation of various α-alkyl-substituted β-aryl-β-ketoesters via dynamic kinetic resolution has been realized in high diastereo- and enantioselectivities for the first time, which led to a variety of optically active anti-β-hydroxyesters in up to 99% ee. The study indicated that the additional stereocenter at the pyridinylmethyl position of these ligands is crucial to realize this hydrogenation.
