A New Class of Iodonium Ylides Engineered as Soluble Primary Oxo and Nitrene Sources

A New Class of Iodonium Ylides Engineered as Soluble Primary Oxo and Nitrene Source

Secondary Bonding as a Force Dictating Structure and Solid-State Aggregation of the Primary Nitrene Sources (Arylsulfonylimino)iodoarenes (ArINSO₂Ar‘)

Iodonium ylides of the form ArINSO2Ar‘ (Ar = m-tolyl, Ar‘ = p-nitrophenyl (1); Ar = m-tolyl, Ar‘ = phenyl (2); Ar = m-tolyl, Ar‘ = p-tolyl (3); Ar, Ar‘ = p-tolyl (4)) have been prepared and crystallographically characterized. Comparisons to previously structurally characterized members of this class of materials (PhINTs (Ts = p-toluenesulfonyl), o-TolylINTs, MesINTs) demonstrate that apparently minor perturbations of the aromatic rings have substantial consequences on the supramolecular assemblies of these materials. The structures range from zig−zag polymers (PhINTs, MesINTs), linear polymers (o-TolylINTs), layered structures (1), two-dimensional ladders (2, 3, o-TolylINTs), to even three-dimensional stepladders (4). Ab initio calculations for a model molecule, PhINSO2Ph, corroborate the presence of a I−N single bond and show considerable charges being localized on the I, N, S, and O atoms (+, −, +, and − charges, respectively). Extensive attractive networks of I···O and I···N secondary bonds thus dominate the solid-state polymers. Within the monomeric units of ArINSO2Ar‘, a U-turn-shaped motif is observed. This structural shape appears to optimize secondary bonding contacts between charged INSO2 arrays. The structures of ArINSO2Ar‘ have been systematically characterized

Novel <i>tert</i>-Butyl Migration in Copper-Mediated Phenol <i>Ortho</i>-Oxygenation Implicates a Mechanism Involving Conversion of a 6-Hydroperoxy-2,4-cyclohexadienone Directly to an <i>o</i>-Quinone

Copper mediated ortho-oxygenation of phenolates may proceed through the generation of a 6-peroxy-2,4-cyclohexadienone intermediate. To test this theory, we studied the fate of sodium 4-carbethoxy-2,6-di-tert-butylphenolate, where the ortho-oxygenation sites are blocked by tert-butyl groups. Using the Cu(I) complex of N,N-bis(2-(N-methylbenzimidazol-2-yl)ethyl)benzylamine, isolation of the major oxygenated product and characterization by single-crystal X-ray crystallography and NMR spectroscopy revealed it to be 4-carbethoxy-3,6-di-tert-butyl-1,2-benzoquinone, resulting from a 1,2-migration of a tert-butyl group. The independently prepared 6-hydroperoxide is transformed by the Cu(I)− (or Cu(II)−) ligand complex to the same o-quinone. The observed 1,2-migration of the tert-butyl group appears to reflect an electron demand created by rearrangement of the postulated peroxy intermediate. A mechanism proceeding alternatively through a catechol and subsequent oxidation to the o-quinone seems ruled out by a control study demonstrating that the requisite intermediate to catechol formation would instead eliminate the 2-tert-butyl group