2845-91-2Relevant academic research and scientific papers
Efficient Suppression of Chain Transfer and Branching via Cs-Type Shielding in a Neutral Nickel(II) Catalyst
Wang, Chaoqun,Kang, Xiaohui,Dai, Shengyu,Cui, Fengchao,Li, Yunqi,Mu, Hongliang,Mecking, Stefan,Jian, Zhongbao
, p. 4018 - 4022 (2021)
An effective shielding of both apical positions of a neutral NiII active site is achieved by dibenzosuberyl groups, both attached via the same donors’ N-aryl group in a Cs-type arrangement. The key aniline building block is accessibl
Catalyst- And Silane-Controlled Enantioselective Hydrofunctionalization of Alkenes by Cobalt-Catalyzed Hydrogen Atom Transfer and Radical-Polar Crossover
Ebisawa, Kousuke,Izumi, Kana,Ooka, Yuka,Kato, Hiroaki,Kanazawa, Sayori,Komatsu, Sayura,Nishi, Eriko,Shigehisa, Hiroki
supporting information, p. 13481 - 13490 (2020/09/02)
The catalytic enantioselective synthesis of tetrahydrofurans, which are found in the structures of many biologically active natural products, via a transition-metal-catalyzed hydrogen atom transfer (TM-HAT) and radical-polar crossover (RPC) mechanism is described herein. Hydroalkoxylation of nonconjugated alkenes proceeded efficiently with excellent enantioselectivity (up to 94% ee) using a suitable chiral cobalt catalyst, N-fluoro-2,4,6-collidinium tetrafluoroborate, and diethylsilane. Surprisingly, the absolute configuration of the product was highly dependent on the steric hindrance of the silane. Slow addition of the silane, the dioxygen effect on the solvent, thermal dependence, and DFT calculation results supported the unprecedented scenario of two competing selective mechanisms. For the less-hindered diethylsilane, a high concentration of diffused carbon-centered radicals invoked diastereoenrichment of an alkylcobalt(III) intermediate by a radical chain reaction, which eventually determined the absolute configuration of the product. On the other hand, a more hindered silane resulted in less opportunity for a radical chain reaction, instead facilitating enantioselective kinetic resolution during the late-stage nucleophilic displacement of the alkylcobalt(IV) intermediate.
Photo-induced phosphorus radical involved semipinacol rearrangement reaction: Highly synthesis of γ-oxo-phosphonates
Wang, Chunhai,Huang, Xiaoling,Liu, Xueting,Gao, Suqian,Zhao, Bin,Yang, Shangdong
supporting information, p. 677 - 680 (2019/08/27)
Hydroxyphosphoric acids display the unique biological activities, and they have some attractive prospects as clinical drug moleculars. Herein, a new approach for the synthesis of γ-oxo-phosphonates (the precursor of hydroxyphosphoric acid) has been established through the semipinacol rearrangement tactic involved the photo-induced phosphorus radical process. Most important, this transformation is avoid of the external oxidants, and occurs very well under the sunlight irradiation, meanwhile the γ-oxo-phosphonate was easily derivatized to obtain γ-hydroxyphosphoric acid, thus highlights the synthesis value of this method.
Access to Optically Enriched α-Aryloxycarboxylic Esters via Carbene-Catalyzed Dynamic Kinetic Resolution and Transesterification
Liu, Bin,Song, Runjiang,Xu, Jun,Majhi, Pankaj Kumar,Yang, Xing,Yang, Song,Jin, Zhichao,Chi, Yonggui Robin
supporting information, p. 3335 - 3338 (2020/04/30)
Optically active α-aryloxycarboxylic acids and their derivatives are important functional molecules. Disclosed here is a carbene-catalyzed dynamic kinetic resolution and transesterification reaction for access to this class of molecules with up to 99% yields and 99:1 er values. Addition of a chiral carbene catalyst to the ester substrate leads to two diastereomeric azolium ester intermediates that can quickly epimerize to each other and thus allows for effective dynamic kinetic resolution to be realized. The optically enriched ester products from our reaction can be quickly transformed to chiral herbicides and other bioactive molecules.
[Ir(COD)Cl]2/tris(2,4-di-t-butylphenyl)phosphite-catalyzed addition reactions of arylboronic acids with aldehydes
Liao, Yuan-Xi,Dong, Jie,Hu, Qiao-Sheng
supporting information, p. 1548 - 1550 (2018/03/26)
[Ir(COD)Cl]2/tris(2,4-di-t-butylphenyl)phosphite-catalyzed addition reactions of arylboronic acids with aldehydes were described. The Ir(I) catalyst, generated from [Ir(COD)Cl]2 and tris(2,4-di-t-butylphenyl)phosphite, was an efficient catalyst system for the addition reactions of a variety of arylboronic acids with aromatic and aliphatic aldehydes. The easy availability of the catalyst and good yields make these reactions potentially useful in organic synthesis.
Porphyrin-Based Air-Stable Helical Radicals
Kato, Kenichi,Furukawa, Ko,Mori, Tadashi,Osuka, Atsuhiro
supporting information, p. 572 - 575 (2018/01/26)
Stable helical radicals are promising multi-functional molecules in light of intriguing magnetic and chiroptical properties. Attempts were made to extend diphenylmethyl-fused NiII porphyrin radical to helical system as the first air-stable orga
6-azabicyclo[3.2.1]octanes via copper-catalyzed enantioselective alkene carboamination
Casavant, Barbara J.,Hosseini, Azade S.,Chemler, Sherry R.
supporting information, p. 2697 - 2702 (2014/09/29)
Bridged bicyclic rings containing nitrogen heterocycles are important motifs in bioactive small organic molecules. An enantioselective copper-catalyzed alkene carboamination reaction that creates bridged heterocycles is reported herein. Two new rings are
Ortho-methylated tribenzotriquinacenes - Paving the way to curved carbon networks
Kirchwehm, Yvonne,Damme, Alexander,Kupfer, Thomas,Braunschweig, Holger,Krueger, Anke
supporting information; experimental part, p. 1502 - 1504 (2012/03/11)
The synthesis of sterically crowded tribenzotriquinacenes with complete and partial methylation of the ortho-positions has been achieved using the double cyclodehydration strategy. This leads to a twisted tribenzotriquinacene core and enables further func
MODULATORS OF C3A RECEPTOR AND METHODS OF USE THEREOF
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Page/Page column 101, (2008/12/07)
Provided are compounds that are modulators of C3a receptor activity, compositions containing the compounds and methods of use of the compounds and compositions. In certain embodiments, the compounds are pyridones. In certain embodiments, provided are methods for treatment or amelioration of diseases associated with modulation of C3a receptor activity.
Design of Bronsted acid-assisted chiral Bronsted acid catalyst bearing a bis(triflyl)methyl group for a Mannich-type reaction
Hasegawa, Aiko,Naganawa, Yuki,Fushimi, Makoto,Ishihara, Kazuaki,Yamamoto, Hisashi
, p. 3175 - 3178 (2007/10/03)
A new Bronsted acid-assisted chiral Bronsted (chiral BBA) acid catalyst (1) was developed by substituting a hydroxy group of optically active 1,1′-bi(2-naphthol) with a stronger Bronsted acidic group such as a bis(trifluoromethanesulfonyl)methyl group. The enantioselective Mannich-type reaction of ketene silyl acetals with aldimines catalyzed by (R)-1 in the presence of stoichiometric achiral proton sources gave (S)-β-amino esters in high yield with moderate to good enantiomeric excesses.
