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Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
Active conformation in amine-thiourea bifunctional organocatalysis preformed by catalyst aggregation
Gábor Tárkányi1, Péter Király, Tibor Soós
1Department of NMR Spectroscopy, Institute of Structural Chemistry, Hungarian Academy of Sciences, Pusztaszeri út 59-67, Budapest, 1025, Hungary. gtarkanyi@chemres.hu
Abstract:
Self-activation: Takemoto's catalyst gains access to its active conformation by equilibrating between its hydrogen-bonded intra- and intermolecular interactions in apolar aprotic solvents. By destabilization of the inactive monomeric conformations, the extended anti-anti thiourea conformation is preformed in the assembly. On leaving the assembly, this transient conformation has a structural preference to become a catalytically active monomeric species that has the potency for dual activation (see scheme).
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