Thiosemicarbazone organocatalysis: tetrahydropyranylation and 2-deoxygalactosylation reactions and kinetics-based mechanistic investigation. Issue 12 (6th October 2017)

• Record Type: Journal Article
• Authors: Larsen, Dennis; Langhorn, Line M.; Akselsen, Olivia M.; Nielsen, Bjarne E.; Pittelkow, Michael
• Is Part Of: Chemical science. Volume 8:Issue 12(2017)
• Page Start: 7978
• Page End: 7982
• Publication Date: 2017-10-06
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7sc03366d
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : Thiosemicarbazones are introduced as a new class of highly tunable and efficient organocatalysts. We showcase this by studies of the tetrahydropyranylation reaction, where insights to the mechanism was achieved by a double Hammett analysis of both the substrate and the catalyst. Abstract : The first use of thiosemicarbazone-based organocatalysis was demonstrated on both tetrahydropyranylation and 2-deoxygalactosylation reactions. The organocatalysts were optimised using kinetics-based selection. The best catalyst outperformed previously reported thiourea catalysts for tetrahydropyranylation by 50-fold. Hammett investigations of both the organocatalyst and the substrate indicate an oxyanion hole-like reaction mechanism.