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Reinecke, Sebastian, Johnson, and Pyun pression, eq 6, may be written as v -(k2/Ki)h0 [CrVI][ RPNO], which agrees with the rate law reported for the oxidation of diphenylmethane in acetic acid.1 2345678 This indicates that the kinetic behavior is essentially the same in both the aqueous sulfuric and the acetic acid system. However, since the value of Ki presum-ably depends on the nature of the anions present,6 the equilibrium constants are not expected to be identical for the two solvent systems.

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The effects of lithium dialkylamide structure, mixed aggregate formation, and solvation on the stereoselectivity of ketone enolization were examined. Of the lithium dialkylamides examined, lithium tetramethylpiperidide (LiTMP) in THF resulted in the best enolization selectivity. The stereoselectivity was further improved in the presence of a LiTMP-butyllithium mixed aggregate. The use of less polar solvents reduced the enolization stereoselectivity. Ab initio calculations predict LDA and LiTMP to form mixed cyclic dimers in ethereal solvents. The calculations also predict LiTMP-alkyllithium mixed aggregates to competitively inhibit the formation of less stereoselective LiTMP-lithium enolate mixed aggregates.

The reactions of isopropylisonitrile with pyridine N-oxide in the presence of chlorine, bromine, and iodine have been studied. Reaction with iodine yields isopropyl isocyanate; the kinetics of the reaction were found to be over-all third order. Reaction with bromine yields an initial adduct (11) whose structure has been determined. Further reaction of I1 with isonitrile yielded isopropyl isocyanate. Reaction of chlorine with isopropylisonitrile and pyridine N-oxide gave the isocyanate in a very slow reaction. Phenyl-and p-anisylisonitriles also gave isocyanates with pyridine N-oxide and iodine; the kinetics were measured and compared with those of isopropyl isocyanate.

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