Enantioselective Michael addition of 1,3-diketones to alkylideneindolenines generated
in situ from arenesulfonylalkylindoles is described, and a series of optically active
C3-alkyl-substituted indole derivatives has been obtained. The resulting adducts can
be readily converted into 3-sec-alkyl-substituted indoles containing a pyrazole skeleton, with direct connection
between the α- and 4-positions, without decrease of the enantioselectivity.
Key words
asymmetric catalysis - Michael addition - arenesulfonylalkylindoles - 1,3-diketones
- pyrazoles