Defluorinative Multi-Functionalization of Fluoroaryl Sulfoxides Enabled by Fluorine-Assisted Temporary Dearomatization

Owing to its unique physical properties, fluorine is often used to open up new reaction channels. In this report, we establish a cooperation of [5,5]-rearrangement and fluorine-assisted temporary dearomatization for arene multi-functionalization. Specifically, the [5,5]-rearrangement of fluoroaryl sulfoxides with & beta;,& gamma;-unsaturated nitriles generates an intriguing dearomatized sulfonium species which is short-lived but exhibits unusually high electrophilicity and thus can be instantly trapped by nucleophiles and dienes at a remarkably low temperature (-95 & DEG;C) to produce four types of valuable multi-functionalized benzenes, respectively, involving appealing processes of defluorination, desulfurization, and sulfur shift. Mechanistic studies indicate that the use of fluorine on arenes not only circumvents the generally inevitable [3,3]-rearrangement but also impedes the undesired rearomatization process, thus provides a precious space for constructing and elaborating the temporarily dearomatized fluorinated sulfonium species.

Automated summary

Due to its unique physical properties, fluorine is frequently used to explore new reaction pathways. This report establishes a cooperative relationship between [5,5]-rearrangement and fluorine-assisted temporary dearomatization for the multi-functionalization of arenes. The use of fluorine not only avoids the [3,3]-rearrangement and hindrances of undesired rearomatization but also provides a valuable space for constructing and elaborating the temporarily dearomatized fluorinated sulfonium species.