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TMS-Prolinol Catalyst in Organocatalysis

Hao Jiang, Lukasz Albrecht, Gustav Dickmeiss, Kim L Jensen, and Karl Anker Jorgensen [Pg.33]

Comprehensive Enantiosekctive Organocatalysis Catalysts, Reactions, and Applications, First Edition. [Pg.33]

The two (i )-isomers have lower, comparable energies, suggesting these are the predominant catalytic intermediates. The computational findings are further supported by X-ray studies on model substrates by Seebach et al. [7]. Moreover, NMR spectroscopic studies by Gschwind et al. of the similar proline-catalyzed self-aldol reaction of propionaldehyde in DMSO verify the presence of an [E-s-trans]-enamine as the only observable intermediate [8]. [Pg.36]

By applying nucleophiles with known nucleophiUcities, the electrophiUcity parameters ( ) could be determined by kinetic experiments. Interestingly, in light of the increased steric bulk, the diarylprolinol catalyst-derived iminium ion was found to be 20 times more reactive than the one formed from pyrrohdine [lOj. This increased reactivity is attributed to the electron-withdrawing effect of the aryl substituents. Notably, the intermediate derived from the imidazolidinone-based catalyst showed the highest electrophilicity. [Pg.38]

60-94% yield 90%- 95% yield 79-88% yield 71-74% yield 54-78% yield 40-75% yield [Pg.36]


I 2 TMS-Prolinol Catalyst in Organocatalysis Formal cycloaddition reactions (as "diene") ... [Pg.46]


See other pages where TMS-Prolinol Catalyst in Organocatalysis is mentioned: [Pg.33]    [Pg.34]    [Pg.36]    [Pg.38]    [Pg.40]    [Pg.42]    [Pg.50]    [Pg.33]    [Pg.34]    [Pg.36]    [Pg.38]    [Pg.40]    [Pg.42]    [Pg.44]    [Pg.50]    [Pg.33]    [Pg.34]    [Pg.36]    [Pg.38]    [Pg.40]    [Pg.42]    [Pg.50]    [Pg.33]    [Pg.34]    [Pg.36]    [Pg.38]    [Pg.40]    [Pg.42]    [Pg.44]    [Pg.50]    [Pg.260]   


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