title: Highly regioselective amination of unactivated alkanes by hypervalent sulfonylimino-λ³-bromane.
abstract: Amination of alkanes has generally required metal catalysts and/or high temperatures. Here we report that simple exposure of a broad range of alkanes to N-triflylimino-λ(3)-bromane 1 at ambient temperature results in C-H insertion of the nitrogen functionality to afford triflyl-substituted amines in moderate to high yields. Marked selectivity for tertiary over secondary C-H bonds was observed; primary (methyl) C-H bonds were inert. Addition of hexafluoroisopropanol to inhibit decomposition of 1 dramatically improved the C-H amination efficiencies. Second-order kinetics, activation parameters (negative activation entropy), deuterium isotope effects, and theoretical calculations suggest a concerted asynchronous bimolecular transition state for the metal-free C-H amination event.
authors.affiliation: Graduate School of Pharmaceutical Sciences, University of Tokushima, 1-78 Shomachi, Tokushima 770-8505, Japan. mochiai@ph.tokushima-u.ac.jp
authors.forename: Masahito
authors.initials: M
authors.lastname: Ochiai
authors.forename: Kazunori
authors.initials: K
authors.lastname: Miyamoto
authors.forename: Takao
authors.initials: T
authors.lastname: Kaneaki
authors.forename: Satoko
authors.initials: S
authors.lastname: Hayashi
authors.forename: Waro
authors.initials: W
authors.lastname: Nakanishi
mesh_terms: D000218:Adamantane / Q000737:chemistry; D000473:Alkanes / Q000737:chemistry*; D000586:Amination; D000588:Amines / Q000737:chemistry*; D001969:Bromobenzenes / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D055598:Chemical Phenomena; D006842:Hydrocarbons, Brominated / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D007700:Kinetics; D013237:Stereoisomerism; D013696:Temperature; D013816:Thermodynamics
chemical_list: D000473:Alkanes; D000588:Amines; D001969:Bromobenzenes; D006842:Hydrocarbons, Brominated; D002244:Carbon; D006859:Hydrogen; D000218:Adamantane