Cyclopropene activation via I(I)/I(III) catalysis: Proof of principle and application in direct tetrafluorination. (5th November 2022)

• Record Type: Journal Article
• Authors: Meyer, Stephanie; Göbel, Lea; Livingstone, Keith; Roblick, Christoph; Daniliuc, Constantin G.; Gilmour, Ryan
• Is Part Of: Tetrahedron. Volume 126(2022)
• Publication Date: 2022-11-05
• Subjects: Cyclopropene -- Fluorination -- Iodine catalysis -- Organocatalysis -- Structural analysis; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2022.132925
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: Preliminary validation of cyclopropene activation by an I(I)/I(III) catalysis manifold is disclosed to enable the direct tetrafluorination of 3, 3-diarylcyclopropenes. This transformation occurs through the in situ generation of ArI(III)F2, with inexpensive iodobenzene, amine·HF complexes and Selectfluor® serving as catalyst, fluoride source and oxidant, respectively. Leveraging this approach, it has been possible to generate four C(sp 3 )-F bonds in a single operation (up to 44%). A Hammett study revealed that the reaction has a very narrow tolerance window with respect to the p -substituent of the aryl groups. Through a process of reaction deconstruction, a mechanism involving two discrete catalytic processes is proposed. Whereas the first cycle results in the ring opening fluorination of the 3, 3-diarylcyclopropene, the second proceeds via a fluorination/phenonium ion rearrangement to liberate a tetrafluorinated diarylethane. This study adds hypervalent iodine catalysis to the plenum of strategies that facilitate cyclopropene activation. Graphical abstract: Image 1