Oxidative Fluoroarylation of Benzylidenecyclopropanes with HF·Py and Aryl Iodides via Iodonio-[3,3]-Rearrangement.

Reported herein is an in situ-generated hypervalent iodine-incorporating fluoroarylation of benzylidenecyclopropanes using commercially available HF·Py and aryl iodides as fluorine and aryl sources, respectively. The reaction proceeds via regioselective 1,2-fluoroiodination of a double bond followed by an iodonio-[3,3]-rearrangement of the formed cyclopropyl-I species. The protocol offers facile access to valuable monofluorinated 1,1-bis-benzyl-alkenes with mild reaction conditions and moderate to good yields.

Iodine(III)-Mediated Fluorination/Semipinacol Rearrangement Cascade of 2-Alkylidenecyclobutanol Derivatives: Access to β-Monofluorinated Cyclopropanecarbaldehydes.

A hypervalent iodine(III)-mediated ring-contractive fluorination reaction of 2-alkylidenecyclobutanol derivatives is presented. The protocol allows the facile synthesis of β-monofluorinated cyclopropanecarbaldehydes via a fluorination/semipinacol rearrangement cascade using nucleophilic Py·HF as the fluorine source. For challenging electron-rich arene substrates, the installation of a protecting group on the free alcohol is pivotal for maintaining the reaction efficiency.

-Difluorination of Methylenecyclopropanes (MCPs) Featuring a Wagner-Meerwein Rearrangement: Synthesis of 2-Arylsubstituted -Difluorocyclobutanes.

The geminal difluorocyclobutane core is a valuable structural element in medicinal chemistry. Strategies for -difluorocyclobutanes, especially the 2-substituted cases, are limiting and often suffer from harsh reaction conditions. Reported herein is a migratory -difluorination of aryl-substituted methylenecycloproanes (MCPs) for the synthesis of 2-arylsubstituted -difluorocyclobutanes.