Highly Enantioselective Friedel-Crafts Reaction of 4,7-Dihydroindoles with β,γ-Unsaturated α-Keto Esters by Chiral Brønsted Acids

Asymmetric Michael addition of 1-acetylindolin-3-ones to β-nitrostyrenes catalyzed by bifunctional thioureas: a simple access to 2-functionalized indoles

The first asymmetric Michael addition of 1-acetylindolin-3-ones to β-nitrostyrenes has been developed. 2-Substituted indolin-3-one derivatives were obtained with excellent yields (up to 99%) and good stereoselectivities (up to 28:1 dr and 92% ee), which could be transformed into 2-functionalized indoles easily without racemization. This achievement might further contribute to the chemistry and pharmacology of indole-related compounds.

Chiral Brønsted acid catalyzed Friedel-Crafts alkylation reactions

The asymmetric Friedel-Crafts reaction is one of the most powerful methods to synthesize optically active aromatic compounds. Particularly, the Friedel-Crafts alkylation of arenes with unsaturated compounds activated by chiral Brønsted acids provides direct access to enantiopure aromatic derivatives with perfect atom economy. In this tutorial review, recent progress in the development of chiral Brønsted acid-catalyzed asymmetric Friedel-Crafts reactions is presented.