Rh(i)-catalyzed enantioselective intramolecular hydroarylation of unactivated ketones with aryl pinacolboronic esters

Abstract

Aryl pinacolboronic esters, which are robust and easily handled boronic acid derivatives, effectively add in an intramolecular 1,2 fashion into unactivated ketone groups in the presence of the rhodium complexes [Rh(cod)(MeCN)₂]BF₄ and a tertiary amine base or [Rh(cod)(OH)]₂ and bisphosphine ligands. The latter set of conditions has been utilized in the enantioselective synthesis of indanols bearing tertiary alcohol groups. The overall transformation serves as a complement to the use of boronic acids as well as traditional nucleophiles such as Grignards, zinc reagents and lithium reagents for enantioselective, intramolecular additions to unactivated ketones, especially those additions which require nucleophilic partners that need to be handled over multiple steps.