Dafydd D. L. Jones, Iskander Douair, L. Maron
Jan 20, 2021
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0
Influential Citations
13
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Journal
Angewandte Chemie
Abstract
The photochemical activation of dimagnesium(I) compounds, and subsequent high yielding, regioselective reactions with inert arenes, are reported. Irradiating benzene solutions of [{( Ar Nacnac)Mg} 2 ] ( Ar Nacnac = [HC(MeCNAr) 2 ] - ; Ar = 2,6-diisopropylphenyl (Dip) or 2,4,6-tricyclohexylphenyl (TCHP)) with blue or UV light, leads to double reduction of benzene and formation of the "Birch-like" cyclohexadienediyl bridged compounds, [{( Ar Nacnac)Mg} 2 (μ-C 6 H 6 )]. Irradiation of [{( Dip Nacnac)Mg} 2 ] in toluene, and each of the three isomers of xylene, promoted completely regio- and chemo-selective C-H bond activations, and formation of [( Dip Nacnac)Mg(Ar')] (Ar' = meta -tolyl; 2,3-, 3,5- or 2,5-dimethylphenyl), and [{( Dip Nacnac)Mg(μ-H)} 2 ]. Fluorobenzene was cleanly defluorinated by photoactivated [{( Dip Nacnac)Mg} 2 ], leading to biphenyl and [{( Dip Nacnac)Mg(μ-F)} 2 ]. Computational studies suggest all reactions proceed via photochemically generated magnesium(I) radicals, which reduce the arene substrate, before C-H or C-F bond activation processes occur.