Michael Addition of Indoles to Enones Catalyzed by a Cationic Iron Salt

Abstract

Indoles are one of the most valuable nucleophiles in Michael additions catalyzed by a proper Lewis acid. In this paper, we found that a cationic iron salt is effective to carry out the Michael addition of indoles. β-Mono- and disubstituted enones reacted smoothly with indoles under our conditions. The cationic iron catalyst is very active, and the maximum TON was up to 425. Moreover, cationic iron-catalyzed conditions enabled a chemoselective Michael addition of a substrate possessing both enone and α,β-unsaturated ester moieties.

Key words

iron - enones - Michael addition - Friedel–Crafts reaction - chemoselectivity

• References

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