Enantioselective photoredox catalysis enabled by proton-coupled electron transfer: development of an asymmetric aza-pinacol cyclization

…, DY Wang, MF Armstrong, RR Knowles

Index: Rono, Lydia J.; Yayla, Hatice G.; Wang, David Y.; Armstrong, Michael F.; Knowles, Robert R. Journal of the American Chemical Society, 2013 , vol. 135, # 47 p. 17735 - 17738

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Citation Number: 76

Abstract

The first highly enantioselective catalytic protocol for the reductive coupling of ketones and hydrazones is reported. These reactions proceed through neutral ketyl radical intermediates generated via a concerted proton-coupled electron transfer (PCET) event jointly mediated by a chiral phosphoric acid catalyst and the photoredox catalyst Ir (ppy) 2 (dtbpy) PF6. Remarkably, these neutral ketyl radicals appear to remain H-bonded to the chiral ...