An efficient method for the synthesis of C3-alkylated indoles has been established
via Brønsted acid catalyzed alkylation of 2-indolylmethanols with azlactones. The
reaction exhibits broad substrate scope and delivers high yields (22 examples, up
to 99% yield). This approach not only provides a new strategy for the direct synthesis
of C3-alkylated indoles, but also represents a rarely reported alkylation between
indole motifs and electron-rich synthons at the C3 position. This protocol serves
as a good example of the application of the umpolung strategy in the synthesis of
C3-alkylated indoles from 2-indolylmethanols.
Key words
C3-alkylation - indole derivatives - azlactone - 2-indolylmethanol
