Diastereoselective Introduction of an Allyl Group to the α′-Position of α-Substituted Pyrrolidines through the Intermediate Formation ofN-Acyliminium Ions

1991 ◽  
Vol 20 (1) ◽  
pp. 81-84 ◽  
Author(s):  
Tatsuya Shono ◽  
Tetsuhiro Fujita ◽  
Yoshihiro Matsumura
Keyword(s):  
Intermediate Formation ◽  
Acyliminium Ions

scholarly journals Synergistic Effect of Alkali Na and K Promoter on Fe-Co-Cu-Al Catalysts for CO2 Hydrogenation to Light Hydrocarbons

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 735
Author(s):  
Yuhao Zheng ◽  
Chenghua Xu ◽  
Xia Zhang ◽  
Qiong Wu ◽  
Jie Liu
Keyword(s):  
Synergistic Effect ◽  
Active Sites ◽  
Intermediate Formation ◽  
Active Phase ◽  
Dissociative Adsorption ◽  
Co2 Hydrogenation ◽  
Chain Growth ◽  
Co2 Conversion ◽  
Light Hydrocarbons ◽  
Active Centers

Alkali metal K- and/or Na-promoted FeCoCuAl catalysts were synthesized by precipitation and impregnation, and their physicochemical and catalytic performance for CO2 hydrogenation to light hydrocarbons was also investigated in the present work. The results indicate that Na and/or K introduction leads to the formation of active phase metallic Fe and Fe-Co crystals in the order Na < K < K-Na. The simultaneous introduction of Na and K causes a synergistic effect on increasing the basicity and electron-rich property, promoting the formation of active sites Fe@Cu and Fe-Co@Cu with Cu0 as a crystal core. These effects are advantageous to H2 dissociative adsorption and CO2 activation, giving a high CO2 conversion with hydrogenation. Moreover, electron-rich Fe@Cu (110) and Fe-Co@Cu (200) provide active centers for further H2 dissociative adsorption and O-C-Fe intermediate formation after adsorption of CO produced by RWGS. It is beneficial for carbon chain growth in C2+ hydrocarbons, including olefins and alkanes. FeCoCuAl simultaneously modified by K-Na exhibits the highest CO2 conversion and C2+ selectivity of 52.87 mol% and 89.70 mol%, respectively.

scholarly journals Cover Picture: Structural Insights into the Trp-Cage Folding Intermediate Formation (Chem. Eur. J. 8/2013)

2013 ◽  
Vol 19 (8) ◽  
pp. 2557-2557
Author(s):  
Petra Rovó ◽  
Pál Stráner ◽  
András Láng ◽  
István Bartha ◽  
Kristóf Huszár ◽  
...  
Keyword(s):  
Intermediate Formation ◽  
Folding Intermediate ◽  
Structural Insights

Olefin cyclisations of hindered α-acyliminium ions

Tetrahedron ◽  
1982 ◽  
Vol 38 (1) ◽  
pp. 209-217 ◽  
Author(s):  
B.P. Wijnberg ◽  
W.N. Speckamp ◽  
A.R.C. Oostveen
Keyword(s):  
Acyliminium Ions

Stereoselective synthesis of O-tosyl azabicyclic derivatives via aza Prins reaction of endocyclic N-acyliminium ions: application to the total synthesis of (±)-epi-indolizidine 167B and 209D

2014 ◽  
Vol 12 (36) ◽  
pp. 7026-7035 ◽  
Author(s):  
Anil K. Saikia ◽  
Kiran Indukuri ◽  
Jagadish Das
Keyword(s):  
Total Synthesis ◽  
Stereoselective Synthesis ◽  
Cyclization Reaction ◽  
Diastereoselective Synthesis ◽  
Prins Reaction ◽  
Prins Cyclization ◽  
Acyliminium Ions

A diastereoselective synthesis of 4-O-tosyl piperidine containing azabicyclic derivatives has been established via Prins cyclization reaction. This protocol has been applied for the total synthesis of (±)-epi-indolizidine 167B and 209D.

ChemInform Abstract: A Highly Enantioselective Mannich Reaction of Aldehydes with Cyclic N-Acyliminium Ions by Synergistic Catalysis.

ChemInform ◽  
2016 ◽  
Vol 47 (1) ◽  
Author(s):  
Francesco Berti ◽  
Federico Malossi ◽  
Fabio Marchetti ◽  
Mauro Pineschi
Keyword(s):  
Mannich Reaction ◽  
Acyliminium Ions ◽  
Synergistic Catalysis
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