Carbene-catalysed reductive coupling of nitrobenzyl bromides and activated ketones or imines via single-electron-transfer process

• DOI: 10.1038/ncomms12933
• Publication Date: 2016-09-27T11:14:23Z
• Authors: Bao-Sheng Li; Yuhuang Wang; Rupert S. J. Proctor; Yuexia Zhang; Richard D. Webster; Song Yang; Baoan Song; Yonggui Robin Chi
• Keywords: Photoredox catalysis; Benzyl alcohol; Organic Synthesis

Abstract Benzyl bromides and related molecules are among the most common substrates in organic synthesis. They typically used as electrophiles nucleophilic substitution reactions. These can also be activated via single-electron-transfer (SET) process for radical Representative recent progress includes α-carbon benzylation of ketones aldehydes photoredox catalysis. Here we disclose generation (nitro)benzyl radicals N -heterocyclic carbene (NHC) catalysis under reductive conditions. The intermediates generated NHC undergo formal 1,2-addition with to eventually afford tertiary alcohol products. overall constitutes a polarity-inversion benzyl bromide, allowing direct coupling two initially electrophilic carbons. Our study provides new carbene-catalysed reaction mode that should enable unconventional transformation mild organocatalytic