Silver nanocluster redox-couple-promoted nonclassical electron transfer: an efficient electrochemical Wolff rearrangement of alpha-diazoketones

Autor: Surendra G. Sudrik, Sambhaji P. Chavan, Harikisan R. Sonawane, Kunjukrishna P. Vijayamohanan, Nirmalya K. Chaki, Vilas B. Chavan, Subhash P. Chavan
Rok vydání: 2005
Předmět:
Zdroj: Chemistry (Weinheim an der Bergstrasse, Germany). 12(3)
ISSN: 0947-6539
Popis: 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.
Databáze: OpenAIRE