title: Adding a Structural Context to the Deprotometalation and Trans-Metal Trapping Chemistry of Phenyl-Substituted Benzotriazole.
abstract: Organometallic bases are becoming increasingly complex, because mixing components can lead to bases superior to single-component bases. To better understand this superiority, it is useful to study metalated intermediate structures prior to quenching. This study is on 1-phenyl-1H-benzotriazole, which was previously deprotonated by an in situ ZnCl2 ⋅TMEDA/LiTMP (TMEDA=N,N,N',N'-tetramethylethylenediamine; TMP=2,2,6,6-tetramethylpiperidide) mixture and then iodinated. Herein, reaction with LiTMP exposes the deficiency of the single-component base as the crystalline product obtained was [{4-R-1-(2-lithiophenyl)-1H-benzotriazole⋅3THF}2 ], [R=2-C6 H4 (Ph)NLi], in which ring opening of benzotriazole and N2 extrusion had occurred. Supporting lithiation by adding iBu2 Al(TMP) induces trans-metal trapping, in which C-Li bonds transform into C-Al bonds to stabilise the metalated intermediate. X-ray diffraction studies revealed homodimeric [(4-R'-1-phenyl-1H-benzotriazole)2 ], [R'=(iBu)2 Al(μ-TMP)Li], and its heterodimeric isomer [(4-R'-1-phenyl-1H-benzotriazole){2-R'-1-phenyl-1H-benzotriazole}], whose structure and slow conformational dynamics were probed by solution NMR spectroscopy.
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL (UK), Fax: (+44) 141-548-4787.
authors.forename: M Ángeles
authors.initials: MÁ
authors.lastname: Fuentes
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL (UK), Fax: (+44) 141-548-4787.
authors.forename: Alan R
authors.initials: AR
authors.lastname: Kennedy
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL (UK), Fax: (+44) 141-548-4787. r.e.mulvey@strath.ac.uk.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Mulvey
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL (UK), Fax: (+44) 141-548-4787.
authors.forename: John A
authors.initials: JA
authors.lastname: Parkinson
authors.affiliation: Snieckus Innovations, Innovation Park, 945 Princess Street, Kingston, Ontario, K7L 3N6 (Canada).
authors.forename: Toni
authors.initials: T
authors.lastname: Rantanen
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL (UK), Fax: (+44) 141-548-4787.
authors.forename: Stuart D
authors.initials: SD
authors.lastname: Robertson
authors.affiliation: Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, K7L 3N6 (Canada).
authors.forename: Victor
authors.initials: V
authors.lastname: Snieckus
keywords: lithium; metalation; structure elucidation; triazoles; zinc