KF/Al2O3as a Highly Efficient, Green, Heterogeneous, and Reusable Catalytic System for the Solvent-Free Synthesis of Carboacyclic Nucleosides via Michael Addition Reaction

2008 ◽  
Vol 39 (1) ◽  
pp. 139-157 ◽  
Author(s):  
Abdolkarim Zare ◽  
Alireza Hasaninejad ◽  
Mohammad Hassan Beyzavi ◽  
Ahmad Reza Moosavi Zare ◽  
Ali Khalafi-Nezhad ◽  
...  
2015 ◽  
Vol 2 (1) ◽  
Author(s):  
C. Gabriela Ávila-Ortiz ◽  
Manuel López-Ortiz ◽  
Alberto Vega-Peñaloza ◽  
Ignacio Regla ◽  
Eusebio Juaristi

AbstractThis article describes a study on the Michael addition reaction of cyclohexanone to nitroolefins catalyzed by the chiral secondary amine (1S,4S)-2-tosyl- 2,5-diazabicyclo[2.2.1]heptane. Reactions were carried out under solvent-free conditions to make them more environmentally friendly. Initially, the observed diastereoand enantioselectivities were moderate to good, but were significantly improved by lowering the reaction temperature. Furthermore, a variety of chiral acids were also tested as co-catalysts in both of their enantiomeric forms, which revealed that (R)-mandelic acid affords excellent results in terms of yield and stereoselectivity. Monitoring the reaction by MS-TOF allowed for the detection of key reaction intermediates, and a reasonable reaction mechanism in which both catalysts are involved is proposed.


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