Intermolecular Anti-Markovnikov Hyrdoamination of Neohexene with Boc-Protected Aryl Sulfonamides Mediated by Oxidative, Photocatalytic Proton-Coupled Electron Transfer: An Investigation into the Effect that the Electronics of the Aryl Sulfonamide Has on Reactivity

Abstract

The task of developing new methods for the formation of C—N bonds occupies a substantial field of chemical research, and much of this effort has been directed towards devising catalytic methods for C—N bond formation via olefin hydroamination. In recent years, the Knowles group has developed an impressive strategy for the intermolecular anti-Markovnikov hydroamination of unactivated olefins with sulfonamides via an oxidative, photocatalytic proton-coupled electron transfer mechanism. This platform was most recently investigated by Rezk (2022), who sought to expand the olefin scope of these hydroamination reactions using Boc-protected aryl sulfonamides. This work seeks to expand Rezk’s findings by investigating the effect that the electronics of the Boc-protected aryl sulfonamides has on their reactivity in the PCET-mediated hydroaminations of neohexene. Unfortunately, efforts at synthesizing some of the desired Boc-protected aryl sulfonamide starting materials proved more challenging than expected. Moreover, attempts at replicating Rezk’s results were surprisingly unsuccessful, along with other attempts at similar PCET-mediated hydroaminations. These results are frustratingly unexpected and point to a potential synthetic roadblock in the use of these hydroamination reactions. More investigation is required in order to understand and remove these roadblocks before the scope of Boc-protected aryl sulfonamides can be effectively elucidated.