scholarly journals Asymmetric hydrogenation of ketones: Tactics to achieve high reactivity, enantioselectivity, and wide scope

2010 ◽  
Vol 86 (3) ◽  
pp. 202-219 ◽  
Author(s):  
Takeshi OHKUMA
Keyword(s):  
Asymmetric Hydrogenation ◽  
High Reactivity ◽  
Wide Scope

ChemInform Abstract: Asymmetric Hydrogenation of Alkenyl, Cyclopropyl, and Aryl Ketones. RuCl2(xylBINAP)(1,2-Diamine) as a Precatalyst Exhibiting a Wide Scope.

ChemInform ◽  
2010 ◽  
Vol 30 (23) ◽  
pp. no-no
Author(s):  
Takeshi Ohkuma ◽  
Masatoshi Koizumi ◽  
Henri Doucet ◽  
Trang Pham ◽  
Masami Kozawa ◽  
...  
Keyword(s):  
Asymmetric Hydrogenation ◽  
Wide Scope ◽  
Aryl Ketones

Design of oxa-spirocyclic PHOX ligands for the asymmetric synthesis of lorcaserin via iridium-catalyzed asymmetric hydrogenation

2021 ◽  
Vol 57 (2) ◽  
pp. 195-198
Author(s):  
Xiang-Yu Ye ◽  
Zhi-Qin Liang ◽  
Cong Jin ◽  
Qi-Wei Lang ◽  
Gen-Qiang Chen ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Asymmetric Hydrogenation ◽  
High Reactivity ◽  
Iridium Complexes ◽  
Oxazoline Ligands

A series of highly rigid oxa-spiro phosphine–oxazoline ligands (O-SIPHOX) were synthesized efficiently, their iridium complexes showed high reactivity and enantioselectivity in the synthesis of key intermediate of anti-obesity drug lorcaserin.

Asymmetric Hydrogenation of Alkenyl, Cyclopropyl, and Aryl Ketones. RuCl2(xylbinap)(1,2-diamine) as a Precatalyst Exhibiting a Wide Scope

1998 ◽  
Vol 120 (51) ◽  
pp. 13529-13530 ◽  
Author(s):  
Takeshi Ohkuma ◽  
Masatoshi Koizumi ◽  
Henri Doucet ◽  
Trang Pham ◽  
Masami Kozawa ◽  
...  
Keyword(s):  
Asymmetric Hydrogenation ◽  
Wide Scope ◽  
Aryl Ketones

scholarly journals Manganese-Catalyzed Asymmetric Hydrogenation of Quinolines Enabled by a Dual “N–H Effect”

2020 ◽  
Author(s):  
Chenguang Liu ◽  
Mingyang Wang ◽  
Shihan Liu ◽  
Yujie Wang ◽  
Yong Peng ◽  
...  
Keyword(s):  
Noble Metal ◽  
Asymmetric Hydrogenation ◽  
High Reactivity ◽  
Catalyst Loading ◽  
Turnover Number ◽  
Noble Metal Catalysts ◽  
Wide Range ◽  
Metal Catalyzed ◽  
High Yields ◽  
Low Catalyst Loading

<p>The first example of non-noble metal-catalyzed asymmetric hydrogenation of aromatic <i>N</i>-heterocycles is reported. A new chiral pincer manganese catalyst showed outstanding catalytic activity in the asymmetric hydrogenation of a wide range of quinolines, affording high yields and excellent enantioselectivities (up to 97% <i>ee</i>). A turnover number of 3840 was reached at a low catalyst loading (S/C=4000), which was competitive with the activity of most effective noble metal catalysts for this reaction. The high reactivity of the manganese catalyst and a precise regulation of the enantioselectivity were ensured by a dual “N–H” effect of the ligand structure.<u></u></p>

Role of Aluminium on the Microstructure and Corrosion Behaviour of Magnesium Prepared by Powder Metallurgy Method

2020 ◽  
Vol 17 (3) ◽  
pp. 8206-8213
Author(s):  
J. Alias
Keyword(s):  
Corrosion Resistance ◽  
Powder Metallurgy ◽  
Corrosion Behaviour ◽  
Corrosion Current ◽  
Optical Microscope ◽  
High Reactivity ◽  
Aluminium Content ◽  
Powder Metallurgy Method ◽  
X Ray Diffraction ◽  
Promising Development

Much research on magnesium (Mg) emphasises creating good corrosion resistance of magnesium, due to its high reactivity in most environments. In this study, powder metallurgy (PM) technique is used to produce Mg samples with a variation of aluminium (Al) composition. The effect of aluminium composition on the microstructure development, including the phase analysis was characterised by optical microscope (OM), scanning electron microscopy (SEM) and x-ray diffraction (XRD). The mechanical property of Mg sample was performed through Vickers microhardness. The results showed that the addition of aluminium in the synthesised Mg sample formed distribution of Al-rich phases of Mg17Al12, with 50 wt.% of aluminium content in the Mg sample exhibited larger fraction and distribution of Al-rich phases as compared to the 20 wt.% and 10 wt.% of aluminium content. The microhardness values were also increased at 20 wt.% and 50 wt.% of aluminium content, comparable to the standard microhardness value of the annealed Mg. A similar trend in corrosion resistance of the Mg immersed in 3.5 wt.% NaCl solution was observed. The corrosion behaviour was evaluated based on potentiodynamic polarisation behaviour. The corrosion current density, icorr, is observed to decrease with the increase of Al composition in the Mg sample, corresponding to the increase in corrosion resistance due to the formation of aluminium oxide layer on the Al-rich surface that acted as the corrosion barrier. Overall, the inclusion of aluminium in this study demonstrates the promising development of high corrosion resistant Mg alloys.

Amâlî (Imla) As Arabic Writing Technique

Metahumaniora ◽  
2017 ◽  
Vol 7 (1) ◽  
pp. 128
Author(s):  
Dicky Rachmat Pauji
Keyword(s):  
Middle East ◽  
Teaching And Learning ◽  
Arabic Language ◽  
Wide Scope ◽  
Writing Style ◽  
Learning Space ◽  
Islamic School ◽  
Related Literature ◽  
Language And Literature ◽  
The Subject

Amâlî (Imla) is a methodology used in studying Arabic language and literature that has a very wide scope. Amâlî (Imla) itself can be translated as: to dictate, to add, to fill in and etc. Amâlî (Imla) may also be interpreted further by the following narration: A teacher (ustadz) comes to a place like a mosque, an Islamic school or any learning space in general. In the process of teaching and learning, all that are spoken by the teacher is written down by the students on pieces of paper they had prepared earlier then be compiled into a book which will be preserved. This paper presents a brief summary of Amâlî (Imla) as a methodology which is discussed in many Amâlî (Imla) related literature works written from the beginning of 7th century until the 14th century. The subject Amâlî (Imla) is written in exceedingly diverse manner, unique to each of numerous known authors. This paper also discusses about various meaning of the word Amâlî (Imla) that has been interpreted differently among authors. In addition, the method of separating chapters and other minor distinct writing style that each of various groups of Amâlî (Imla) authors had developed was presented in this work. And lastly, this paper discusses the fact that Amâlî (Imla) related textbook authors were not only originated from the Middle East, but also from regions such as Iran (Huzistan) and Andalusia

Bimetallic Radical Redox-Relay Catalysis for the Isomerization of Epoxides to Allylic Alcohols

2019 ◽  
Author(s):  
Ke-Yin Ye ◽  
Terry McCallum ◽  
Song Lin
Keyword(s):  
Ring Opening ◽  
High Reactivity ◽  
Hydrogen Atom Transfer ◽  
Organic Radicals ◽  
Epoxide Ring ◽  
Allylic Alcohols ◽  
Epoxide Ring Opening ◽  
Bond Forming ◽  
Co Catalysts ◽  
The Rich

Organic radicals are generally short-lived intermediates with exceptionally high reactivity. Strategically, achieving synthetically useful transformations mediated by organic radicals requires both efficient initiation and selective termination events. Here, we report a new catalytic strategy, namely bimetallic radical redox-relay, in the regio- and stereoselective rearrangement of epoxides to allylic alcohols. This approach exploits the rich redox chemistry of Ti and Co complexes and merges reductive epoxide ring opening (initiation) with hydrogen atom transfer (termination). Critically, upon effecting key bond-forming and -breaking events, Ti and Co catalysts undergo proton-transfer/electron-transfer with one another to achieve turnover, thus constituting a truly synergistic dual catalytic system.<br>

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