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The anomerization of the tetra-0-acetyl-D-glucopyranosyl chlorides in acetonitrile is first order in chloride ion. Experiments with 3GCl-labelled chloride ion showed the reaction t o involve nucleophilic attack ( S N~) by chloride ion a t the anomeric center. The reaction is accompanied by a faster dissociation of the p-anomer (I) to the l,2-acetoxonium ion. Although the rate of anomerization was slightly accelerated by addition of benzene, the ionic reaction was strongly suppressed. Bromide ion was less effective than chloride ion in catalyzing the reaction and iodide ion was least effective. Reaction of tetra-0-acetyl-cr-~-glucop~ranos~l bromide with tetraethylammonium chloride in acetonitrile rapidly gave I in high yield. The anomeric effect for chlorine appears to be about 2 Ircal/mole.

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Bis(acetylacetonato)copper(II) was sensitized by some ketones with a wide range of triplet energies to undergo photodecomposition to give the same products as that obtained in the direct photolysis but with much better efficiency. Other sensitizers such as fluorenone and aromatic hydrocarbons failed to sensitize the reaction. There exists no correlation of the sensitizer triplet energies with the sensitization results. This, and rapid quenching processes, indicated that the classical energy transfer process was unlikely. The sensitization process by an electron transfer within an encounter complex was proposed to explain the decomposition of Cu(acac)2; the calculated free energy changes (ΔG) associated with the electron transfer from the available data support the proposal. Chemical reactions of excited state anthracene and 1-cyanonaphthalene with Cu(acac)2 may also occur. Irradiation of Cu(acac)2 in the presence of triphenylphosphine and benzophenone led to an excellent yield of Cu(acac)(PPh3)2 without causing precipitation of copper(I) complexes.

Tetra-0-acetyl-p-D-glucopyranosyl halides and phenoxides in solution in acetonitrile showed a specific deshielding of H-1, H-3, and H-5 on addition of tetraethylammonium halides. The shifts and equilibrium constants increased as the anion radius decreased. The ortho hydrogens of the phenoxide aglucons were also significantly deshielded. The strong dependence of the equilibrium constants of the phenoxide compounds on p-substituents indicated considerable involvement of the phenyl groups in a specific conformation. A simple electrostatic model was successful in correlating the energies and predicting the structures of the complexes. It was not necessary to postulate specific hydrogen bonding to account for association of the anion with an electrophilic region of the molecule. The calculations required specific orientations of acetoxy groups with respect to the pyranose ring which are consistent with those of related studies. In favorable circumstances, the method may be used as a probe for electrophilic regions in molecules.