Anions involved in initiation of the thermal induced SRN1 reaction for alfa-arylation of ketones

DANIEL A. CAMINOS; MARCELO PUIATTI; BARDAGI JAVIER IVAN; ALICIA B. PEÑÉÑORY

RSC Advances

Royal Society of Chemistry

Lugar: Londres; Año: 2017 vol. 7 p. 31148 - 31148

2046-2069

he SRN1 reaction between acetophenone enolate and PhI is thermally induced and accelerated by microwave irradiation to give the corresponding substitution product 1,2-diphenylethanone in a 50% yield in DMSO at 70ºC. Regarding the mechanism of initiation, in this reaction, acetophenone enolate, tert-butoxyde anion and dimsyl anion (the ionic form of the solvent) could promote the initial electron transfer to start the radical reaction. Comparative studies on the PhI dehalogenation promoted by the different anions were conducted in DMSO under microwave irradiation and by quantum calculations. Dimsyl anion shows a higher Iodide generation even at lower concentrations than acetofenone enolate and tBuO-. Likewise, DFT calculation by B3PW91, M062X and PBE0 shows dymsil anion as the best electron donor. While the three anion can initiate the radical reaction, the reactivity order found locates the dimsyl anion in the first place, followed by the enolate of acetophenone and then the alkoxide.