Mechanistic interrogation of the asymmetric lithiation-trapping of N-thiopivaloyl azetidine and pyrrolidine

2016 ◽  
Vol 52 (7) ◽  
pp. 1354-1357 ◽  
Author(s):  
Peter J. Rayner ◽  
Joshua C. Smith ◽  
Charline Denneval ◽  
Peter O'Brien ◽  
Paul A. Clarke ◽  
...  
Keyword(s):  
Asymmetric Induction ◽  
Fundamental Study ◽  
Chiral Diamine ◽  
Dynamic Resolution

A fundamental study on the mechanism of the s-BuLi/chiral diamine-mediated asymmetric lithiation-trapping of N-thiopivaloyl azetidine and pyrrolidine has revealed that the asymmetric induction is due to a dynamic resolution of configurationally unstable organolithiums.

scholarly journals Untethering sparteine: 1,3-diamine ligand for asymmetric synthesis in water

2021 ◽  
Author(s):  
Fanyun Zeng ◽  
Chen Chen ◽  
Liu Liu ◽  
Yifan Li ◽  
Bo Li ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Cinchona Alkaloids ◽  
Phosphine Ligands ◽  
Asymmetric Induction ◽  
Asymmetric Reaction ◽  
Asymmetric Transformations ◽  
Chiral Diamine ◽  
Amine Ligands ◽  
Further Development ◽  
Reaction In Water

Chiral ligands are the toolbox for asymmetric synthesis to access 3D molecular world. Enabling efficient asymmetric reaction in water is a big challenge. As moisture/air stable and strong binding moieties, amines, compared to imine and phosphine ligands, are ideal candidates to accommodate asymmetric transformations in water. Known amine ligands like Proline analogues and Cinchona alkaloids showed excellent asymmetric induction. Sparteine, an alkaloid studied originated in 1968, had never been considered as a privileged catalyst due to its structure defection which led to poor reaction compatibility and unsatisfactory stereoselectivity. Here, we report the design of a chiral diamine catalyst untethering one of the sparteine rings. The diamine catalyst was easily accessed in two steps on 100 gram-scale. This chiral ligand was proved to be efficient for addition reactions in water providing products with excellent yields and enantiomeric ratios. This pluripotent catalyst has also shown good reactivity/enantioselectivity under organocatalysis, Cu and Pd-catalysed conditions. We anticipate that the ligand would allow further development of other catalysts for important yet challenging green stereoselective transformations.

Fundamental Study on Application of the Nanocomposite to an Electrical Rotating Machine

2017 ◽  
Vol 137 (11) ◽  
pp. 645-651
Author(s):  
Kotaro Mura ◽  
Toshihiro Tsuda ◽  
Tetsuo Yoshimitsu ◽  
Takuya Onishi ◽  
Shuichiro Hashimoto ◽  
...  
Keyword(s):  
Fundamental Study ◽  
Rotating Machine

Fundamental Study for Locating Water Tree Degradation in XLPE Cables

2015 ◽  
Vol 135 (7) ◽  
pp. 424-430 ◽  
Author(s):  
MyongHwan Kim ◽  
Yoshinobu Murakami ◽  
Masayuki Nagao ◽  
Naohiro Hozumi ◽  
Takashi Kurihara ◽  
...  
Keyword(s):  
Fundamental Study ◽  
Water Tree
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