Abstract
We report the application of the Pd(II)-catalyzed, directing-group-aided C–H arylation/alkylation
tactics to functionalize the pyrene core, especially, the relatively inaccessible
C2 and K-region C10 positions of the pyrene core and augmentation of the library of
pyrene derivatives with C1,C2- and C1,C10-disubstituted pyrene motifs. The Pd(II)-catalyzed
β-C–H arylation/alkylation of the C2-position of pyrene-1-carboxamide possessing an
8-aminoquinoline directing group yielded various C1,C2-disubstituted pyrenes. Similarly,
the Pd(II)-catalyzed selective γ-C–H arylation/alkylation of the C10-position of N-(pyren-1-yl)picolinamide, possessing a picolinamide directing group, yielded various
C1,C10-disubstituted pyrenes. Examples of C(9)–H arylation of pyrene-1-carboxamide
and the removal of the directing group after the C–H arylation/alkylation reactions
were also shown. The structures of representative pyrene derivatives were confirmed
by the X-ray structure analysis. Given the importance of the pyrene derivatives in
various fields of chemical sciences, this report is a contribution towards augmentation
of the library of pyrene derivatives with C1,C2- and C1,C10-disubstituted pyrene amide
motifs.
Key words
C–H activation - C–H arylation/alkylation - C–H functionalization - bidentate directing
group - carboxamides - palladium - pyrene