Development of Dynamic Asymmetric Organocatalysis and Their Mechanistic Studies

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We have designed and developed 1, 3-diamine-tethered guanidine/bisthiourea organocatalysts for catalytic asymmetric 1, 4-additions including 1) Friedel-Crafts alkylation of phenols and 2) phospha-Michael reactions. Kinetic analyses using Eyring plots uncovered that differences in the activation entropies(ΔΔS^‡) play a principal role in the stereodiscrimination of the developed F-C reactions. We also found that, in the phospha-Michael reactions, either the monomeric or oligomeric active species of the catalyst can be utilized depending on the solvent system.