title: KOtBu: A Privileged Reagent for Electron Transfer Reactions?
abstract: Many recent studies have used KOtBu in organic reactions that involve single electron transfer; in the literature, the electron transfer is proposed to occur either directly from the metal alkoxide or indirectly, following reaction of the alkoxide with a solvent or additive. These reaction classes include coupling reactions of halobenzenes and arenes, reductive cleavages of dithianes, and SRN1 reactions. Direct electron transfer would imply that alkali metal alkoxides are willing partners in these electron transfer reactions, but the literature reports provide little or no experimental evidence for this. This paper examines each of these classes of reaction in turn, and contests the roles proposed for KOtBu; instead, it provides new mechanistic information that in each case supports the in situ formation of organic electron donors. We go on to show that direct electron transfer from KOtBu can however occur in appropriate cases, where the electron acceptor has a reduction potential near the oxidation potential of KOtBu, and the example that we use is CBr4. In this case, computational results support electrochemical data in backing a direct electron transfer reaction.
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde , 295 Cathedral Street, Glasgow G1 1XL, U.K.|GlaxoSmithKline Medicines Research Centre , Gunnels Wood Road, Stevenage SG1 2NY, U.K.
authors.forename: Joshua P
authors.initials: JP
authors.lastname: Barham
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde , 295 Cathedral Street, Glasgow G1 1XL, U.K.
authors.forename: Graeme
authors.initials: G
authors.lastname: Coulthard
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde , 295 Cathedral Street, Glasgow G1 1XL, U.K.
authors.forename: Katie J
authors.initials: KJ
authors.lastname: Emery
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde , 295 Cathedral Street, Glasgow G1 1XL, U.K.
authors.forename: Eswararao
authors.initials: E
authors.lastname: Doni
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde , 295 Cathedral Street, Glasgow G1 1XL, U.K.
authors.forename: Florimond
authors.initials: F
authors.lastname: Cumine
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde , 295 Cathedral Street, Glasgow G1 1XL, U.K.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Nocera
authors.affiliation: GlaxoSmithKline Medicines Research Centre , Gunnels Wood Road, Stevenage SG1 2NY, U.K.
authors.forename: Matthew P
authors.initials: MP
authors.lastname: John
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde , 295 Cathedral Street, Glasgow G1 1XL, U.K.
authors.forename: Leonard E A
authors.initials: LE
authors.lastname: Berlouis
authors.affiliation: AstraZeneca R&D , The Darwin Building, Milton Road, Milton, Cambridge CB4 0FZ, U.K.
authors.forename: Thomas
authors.initials: T
authors.lastname: McGuire
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde , 295 Cathedral Street, Glasgow G1 1XL, U.K.
authors.forename: Tell
authors.initials: T
authors.lastname: Tuttle
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde , 295 Cathedral Street, Glasgow G1 1XL, U.K.
authors.forename: John A
authors.initials: JA
authors.lastname: Murphy