From 1,2-Diborylalkenes to Functionalized Indenols: Tandem Suzuki Coupling-Intramolecular Cyclization.

Abstract

A concise and efficient domino strategy for the synthesis of symmetrically 2,3-disubstituted indenols has been developed via palladium-catalyzed Suzuki coupling of readily accessible 1,2-diborylalkenes with substituted 2-bromoaryl carbonyl compounds. The reaction proceeds efficiently, with palladium playing a dual role by mediating C-C bond formation and promoting subsequent intramolecular cyclization through nucleophilic addition of the boronic ester to the carbonyl. Furthermore, a Lewis acid-promoted regioselective approach to 2-substituted indenols and methoxyindenes from terminal 1,2-diborylalkenes via Suzuki-Miyaura coupling is disclosed under mild conditions.