title: Cobalt-catalysed site-selective intra- and intermolecular dehydrogenative amination of unactivated sp(3) carbons.
abstract: Cobalt-catalysed sp(2) C-H bond functionalization has attracted considerable attention in recent years because of the low cost of cobalt complexes and interesting modes of action in the process. In comparison, much less efforts have been devoted to the sp(3) carbons. Here we report the cobalt-catalysed site-selective dehydrogenative cyclization of aliphatic amides via a C-H bond functionalization process on unactivated sp(3) carbons with the assistance of a bidentate directing group. This method provides a straightforward synthesis of monocyclic and spiro β- or γ-lactams with good to excellent stereoselectivity and functional group tolerance. In addition, a new procedure has been developed to selectively remove the directing group, which enables the synthesis of free β- or γ-lactam compounds. Furthermore, the first cobalt-catalysed intermolecular dehydrogenative amination of unactivated sp(3) carbons is also realized.
authors.affiliation: Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, 402 N. Blackford Street, Indianapolis, Indiana 46202, USA.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Wu
authors.affiliation: Institute of Chemistry and BioMedical Sciences, Nanjing University, Nanjing 210093, P.R. China.
authors.forename: Ke
authors.initials: K
authors.lastname: Yang
authors.affiliation: Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, 402 N. Blackford Street, Indianapolis, Indiana 46202, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Institute of Chemistry and BioMedical Sciences, Nanjing University, Nanjing 210093, P.R. China.
authors.forename: Hao
authors.initials: H
authors.lastname: Sun
authors.affiliation: 1] Institute of Chemistry and BioMedical Sciences, Nanjing University, Nanjing 210093, P.R. China [2] Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, USA.
authors.forename: Guigen
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, 402 N. Blackford Street, Indianapolis, Indiana 46202, USA.
authors.forename: Haibo
authors.initials: H
authors.lastname: Ge