title: Silver nanocluster redox-couple-promoted nonclassical electron transfer: an efficient electrochemical Wolff rearrangement of alpha-diazoketones.
abstract: In this work we report the unique electrocatalytic role of benzoic acid protected silver nanoclusters (Ag(n), mean core diameter 2.5 nm) in the Wolff rearrangement (Scheme 1) of alpha-diazoketones. More specifically, the presence of a Ag(n) (0)/Ag(n) (+) redox couple facilitates a nonclassical electron-transfer process, involving chemical reaction(s) interposed between two electron-transfer steps occurring in opposite directions. Consequently, the net electron transfer between the electron mediator (Ag(n)) and alpha-diazoketone is zero. In-situ UV-visible studies using pyridine as a nucleophilic probe indicate the participation of alpha-ketocarbene/ketene as important reaction intermediates. Controlled potential coulometry of alpha-diazoketones using Ag(n) as the anode results in the formation of Wolff rearranged carboxylic acids in excellent yield, without sacrificing the electrocatalyst.
authors.affiliation: Division of Organic Chemistry: Technology, National Chemical Laboratory, Pune, India.
authors.forename: Surendra G
authors.initials: SG
authors.lastname: Sudrik
authors.forename: Nirmalya K
authors.initials: NK
authors.lastname: Chaki
authors.forename: Vilas B
authors.initials: VB
authors.lastname: Chavan
authors.forename: Sambhaji P
authors.initials: SP
authors.lastname: Chavan
authors.forename: Subhash P
authors.initials: SP
authors.lastname: Chavan
authors.forename: Harikisan R
authors.initials: HR
authors.lastname: Sonawane
authors.forename: K
authors.initials: K
authors.lastname: Vijayamohanan