Room-temperature sodium metal reduction of phenyl isocyanate (PhNCO) in hexamethylphosphoramide yields the anion radical (PhNCO(•-)) where the unpaired electron exhibits coupling to one nitrogen and five unique protons. The extent of coupling to the carbon in the NCO group was obtained via the reduction of (13)C-labeled PhN(13)CO. Remarkably, this coupling is over 2 orders of magnitude smaller than that found for the alkyl-substituted analogue. This large attenuation indicates that the electron is not localized within the isocyanate group (as in the alkyl analogues) but is distributed throughout the entire π system including the phenyl ring. The consequence of this delocalization is that the isocyanate is expected to remain linear upon reduction of PhNCO. The anion radicals of p-tolyl- and p-methoxyphenyl isocyanate have also been generated. We find that these electron-donating substituents on the phenyl ring have little effect on the nitrogen coupling. Hence, the NCO group has the same geometry as the PhNCO(•-). When PhNCO is reduced in tetrahydrofuran, a solvent where ion association effects are common, PhNCO(•-) is not observed. Here, a cyclotrimerization occurs (initiated by PhNCO(•-)), generating the triphenyl isocyanurate anion radical where the unpaired electron is predominately localized in one of the carbonyl moieties.

The exposure of 2,4,6-tri-tert-butylphenol (1) in solution to NO 2 · results in the rapid formation of 2,4,6-tri-tert-butyl-4-nitro-2,5-cyclohexadienone (2), which then undergoes a slow (ca. 3 d) rearrangement in the absence of air. The mechanism that describes this rearrangement is understood for the first time and involves the initial isomerization of 2 to form a (-ONO)-substituted cyclohexadieneone (6). The nitrite moiety undergoes bond homolysis releasing NO · while forming

Room‐temperature potassium metal reduction of 1‐naphthyl isocyanate in THF results in a rapid cyclotrimerization (initiated by the 1‐naphthyl isocyanate anion radical) that generates two diastereoisomers (atropisomers) of tris(1‐naphthyl) isocyanurate. The formation of the syn and anti diastereoisomers was monitored by 1H and 13C NMR spectroscopy. Upon completion of the cyclotrimerization, the two diastereoisomers were isolated, and their configuration was assigned by NMR spectroscopy. Both compounds crystallize in the monoclinic C2/c space group, and single‐crystal X‐ray diffraction analyses confirm the structures of both isomeric forms. The results from this study prove that alkali metal reduction of isocyanates is a convenient and rapid method for generating isocyanurate compounds even when a sterically bulky substituent is attached to the NCO moiety.