Oxalates as Activating Groups for Tertiary Alcohols in PhotoredoxCatalyzed gem-Difluoroallylation To Construct All-Carbon Quaternary Centers

Construction of challenging and important all-carbon quaternary centers has received growing attention. Herein, with oxalates as activating groups for tertiary alcohols, we report photoredox-catalyzed gem-difluoroallylation to construct all-carbon quaternary centers enabled by efficient tertiary radical addition to alpha-trifluoromethyl alkenes. This transformation shows good functional group tolerance for both alpha-trifluoromethyl alkenes and oxalates. Moreover, this strategy is also successfully applied to the synthesis of monofluoralkenes from the corresponding electron- rich gem-difluoroalkenes and cesium tertiary alkyl oxalates under modified conditions.

Automated summary

In this work, a photoredox-catalyzed gem-difluoroallylation was reported for the construction of all-carbon quaternary centers using oxalates as activating groups for tertiary alcohols. Efficient tertiary radical addition to alpha-trifluoromethyl alkenes enabled the formation of these challenging structures. The method showed good functional group tolerance for both alpha-trifluoromethyl alkenes and oxalates, and was successfully applied to the synthesis of monofluoralkenes.