Synthesis and Properties of Chiral Thioureas Bearing an Additional Function at a Remote Position Tethered by a 1,5-Disubstituted Triazole

Abstract

The synthesis and properties of multifunctional thioureas bearing a variety of functional groups at a position remote from the thiourea moiety are described. A 1,5-disubstituted triazole tether connected with a thiourea and another functional group was synthesized via ruthenium catalyzed Huisgen cycloaddition. We demonstrate the utility of the synthetic thioureas as asymmetric catalysts and probes for the mechanistic elucidation of the course of the Michael reaction of an α,β-unsaturated imide.

Ruthenium-Catalyzed Azide Alkyne Cycloaddition Reaction: Scope, Mechanism, and Applications

“…Screening of three of the catalysts in the enantioselective conjugate addition of cyclohexanone to trans -β-nitrostyrene afforded up to 92% ee. In a later study, the scope of aryl-substituted nitroolefins was expanded, with a 2-furyl-substituted nitroolefin affording up to 98% ee using these organocatalysts …”

“…In a later study, the scope of aryl-substituted nitroolefins was expanded, with a 2-furylsubstituted nitroolefin affording up to 98% ee using these organocatalysts. 245 7. SUPRAMOLECULAR STRUCTURES, NANOCHEMISTRY, AND ELECTRONIC DEVICES Triazole formation provides a convenient method for elaborating supramolecular structures, which often contain a complex central scaffold and require a simple and high-yielding reaction for the final step.…”

“…245 Figure 29. Synthesis of trifunctional organocatalysts for Michael additions to nitroolefins [244][245] 7. SUPRAMOLECULAR STRUCTURES, NANOCHEMISTRY AND ELECTRONIC…”

Characterization of some amino acid derivatives of benzoyl isothiocyanate: Crystal structures and theoretical prediction of their reactivity

“…Urea and thiourea derivatives of diphenylphoshoramidate may be accessed by the reaction of diphenylphosphoramidate with aromatic isocyanates and isothiocyanates in tetrahydrofuran in the presence of triethylamine [9]. Multifunctional thioureas bearing a variety of functional groups at a position remote from the thiourea moiety have been synthesized via ruthenium catalyzed Huisgen cycloaddition [10]. The aspartic acid dimethyl ester and alanine methyl ester derivatives of benzoyl isothiocyanate have also been synthesized in acetone from the corresponding thione [11,12].…”

Enantioselective Reactions of N‐Acyliminium Ions Using Chiral Organocatalysts

“…[39] In a bifunctional thiourea catalyst, the hydrogen-bond donor in the catalyst is used to activate the electrophile, whereas the Lewis base is used to activate the nucleophile. [40] Selective nucleophilic attack, that is, at one face of the prochiral carbon, was achieved by chiral substituents on the thiourea catalyst. Therefore, the design of thiourea catalysts bearing effective chiral substituents is necessary to improve enantioselectivity in thiourea-catalyzed transformations.…”