Electrophotocatalysis Enables Birch‐Type Dearomative Alkylation

Abstract

ABSTRACT Birch‐type dearomative alkylation of (hetero)arenes is straightforward for constructing skeletons bearing sp 3 ‐hybridized carbon centers. However, such a tandem reaction suffers from competitive protonation and intractable alkylation, leading to the formation of 1,4‐cyclohexadienes rather than dearomative alkylation in a one‐pot reaction. Herein we report the first electrophotocatalytic Birch‐type dearomative alkylation of (hetero)arenes. Using N,N ‐bis(2,6‐diisopropylphenyl)perylene‐3,4,9,10‐bis(dicarboximide) as an electrophotocatalyst and alkyl chlorides as alkylating agents, a range of anthracene, naphthalene and acridine derivatives have been successfully converted into their dearomatively alkylated frameworks. Control experiments, spectroscopic studies and DFT calculations revealed that tetrabutylammonium‐stabilized arene radical anions can react with alkyl chlorides under metal‐free conditions via “Birch‐S N 2” or “XAT‐SR N 1” pathway. The extremely mild reaction conditions, high site selectivity and diverse functional group tolerance, together with the simulated sunlight trials and the utilization of solar electricity, highlight promising potential of this tandem reaction in directly modifying (hetero)arenes with various electrophiles.