title: Nickel-Catalyzed Boron Insertion into the C2-O Bond of Benzofurans.
abstract: Treatment of benzofurans with bis(pinacolato)diboron and Cs2CO3under nickel-NHC catalysis resulted in the insertion of a boron atom into the C2-O bond of benzofurans to afford the corresponding oxaborins. The scope of benzofuran substrates is wide, and the reactions proceeded without loss of functional groups such as fluoro, methoxy, and ester that are potentially reactive under nickel catalysis. The boron-inserted products proved to be useful building blocks and subsequently underwent a series of transformations, one of which led to the synthesis of fluorescent π-expanded oxaborins.
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University , Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Hayate
authors.initials: H
authors.lastname: Saito
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University , Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Otsuka
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University , Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Nogi
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University , Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Yorimitsu