Royal Society of Chemistry, Chemical Science, 12(3), p. 3436, 2012
DOI: 10.1039/c2sc21298f
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Oxime carbonates have been synthesised and their potential studied as a new class of radical precursor. A general synthetic route, avoiding laboratory use of phosgene, was developed. Alkyl or aryl 1H-imidazole-1-carboxylates were prepared from the corresponding alcohols and 1,1-carbonyldiimidazole, then reacted with oximes in the presence of base. UV photolyses of oxime carbonates released particular N- and O-centred radicals suitable for spectroscopic examination. Spiro-cyclisations of alkoxycarbonyloxyl radicals onto aromatic acceptors and 5-exo cyclisations onto alkene acceptors were studied by EPR spectroscopy. EPR data also provided insight to the loss of CO₂ from alkoxycarbonyloxyl radicals. The conformational preferences of 2-oxo-1,3-dioxolan-4-yl-methyl and related radicals were established. Modest yields of cyclic carbonates were obtained from preparative scale photolyses. ; 9 page(s)