1258314-00-9Relevant articles and documents
Linking conformational flexibility and kinetics: Catalytic 1,4-type friedel-crafts reactions of phenols utilizing 1,3-diamine-tethered guanidine/bisthiourea organocatalysts
Sohtome, Yoshihiro,Shin, Bongki,Horitsugi, Natsuko,Noguchi, Keiichi,Nagasawa, Kazuo
, p. 2463 - 2470 (2011)
Herein, we present details of our conformationally flexible, 1,3-diamine-tethered guanidine/bisthiourea organocatalysts for chemo-, regio-, and enantioselective 1,4-type Friedel-Crafts reactions of phenols. These organocatalysts show a unique stereo-discrimination governed by the differential activation entropy (δδS+), rather than by the differential activation enthalpy (δδH+). Extensive kinetic analyses using Eyring plots for a series of guanidine/bisthiourea organocatalysts revealed the key structural motif in the catalysts associated with a large magnitude of differential activation entropy (δδS +). A plausible guanidine-thiourea cooperative mechanism for the enantioselective Friedel-Crafts reaction is proposed. Copyright
Entropy-controlled catalytic asymmetric 1,4-type Friedel-crafts reaction of phenols using conformationally flexible guanidine/bisthiourea organocatalyst
Sohtome, Yoshihiro,Shin, Bongki,Horitsugi, Natsuko,Takagi, Rika,Noguchi, Keiichi,Nagasawa, Kazuo
supporting information; experimental part, p. 7299 - 7303 (2010/11/04)
Soft and weak cooperation: Conformationally flexible organic compounds were found to promote the title transformation. These "soft" organocatalysts, which are able to control processes through the differential activation entropies (ΔΔS*S-R) of