Divergent Access to Benzocycles through Copper-Catalyzed Borylative Cyclizations

A copper-catalyzed chemodivergent approach to five- and six-membered benzocycles from dienyl arenes tethered with a ketone has been developed. Through proper choice of coordinating ligands and catalytic conditions, copper-catalyzed borylative cyclization of a single dienyl arene can be diverted to two different pathways, leading to indanols and dihydronaphthalenols with high stereoselectivity. The chiral bidentate bisphosphine ligand (S,S)-Ph-BPE was optimal for asymmetric copper-allyl addition to a tethered ketone via a boat-like transition state, whereas NHC ligands led to boro-allyl addition producing indanols with high diastereoselectivity.

Automated summary

A copper-catalyzed chemodivergent approach has been developed for the synthesis of five- and six-membered benzocycles from dienyl arenes tethered with a ketone. By selecting appropriate coordinating ligands and catalytic conditions, the reaction can be diverted to two different pathways, leading to the formation of indanols and dihydronaphthalenols with high stereoselectivity. The use of chiral bidentate bisphosphine ligand (S,S)-Ph-BPE was found to be optimal for asymmetric copper-allyl addition to a tethered ketone, while NHC ligands resulted in boro-allyl addition producing indanols with high diastereoselectivity.