title: Copper-Catalyzed Oxyboration of Unactivated Alkenes.
abstract: The first regiodivergent oxyboration of unactivated terminal alkenes is reported, using copper alkoxide as a catalyst, bis(pinacolato)diboron [(Bpin)2 ] as a boron source, and (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) as an oxygen source. The reaction is compatible with various functional groups. Two regioisomers are selectively produced by selecting the appropriate ligands on copper. The products may be used as a linchpin precursor for various other functionalizations, and net processes such as carbooxygenation, aminooxygenation, and dioxygenation of alkenes can be achieved after C-B bond transformations. Mechanistic studies indicate that the reaction involves the following steps: 1) Transmetalation between CuOtBu and (Bpin)2 to generate a borylcopper species; 2) regiodivergent borylcupration of alkenes; 3) oxidation of the thus-generated C-Cu bond to give an alkyl radical; 4) trapping of the resulting alkyl radical by TEMPO.
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan).
authors.forename: Taisuke
authors.initials: T
authors.lastname: Itoh
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan).
authors.forename: Takumi
authors.initials: T
authors.lastname: Matsueda
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan). y-shimizu@mol.f.u-tokyo.ac.jp.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Shimizu
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan). kanai@mol.f.u-tokyo.ac.jp.|JST, ERATO, Kanai Life Science Catalysis Project, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan). kanai@mol.f.u-tokyo.ac.jp.
authors.forename: Motomu
authors.initials: M
authors.lastname: Kanai
keywords: alkenes; boration; copper; difunctionalization; radical reactions