Convenient one-pot synthesis of trans-1,2-diaryloxiranes from the direct coupling of benzyl halides.

trans-1,2-Diaryloxiranes were conveniently prepared in an one-pot reaction by the direct coupling of benzyl halides in the presence of silver oxide and DMSO under mild conditions.

Convenient oxidation of benzylic and allylic halides to aldehydes and ketones.

Benzylic and allylic halides were conveniently oxidized to aldehydes and ketones by pyridine N-oxide in the presence of silver oxide under mild conditions.

Surprisingly low aqueous acidity at the alpha-positions of pyridiniums and pyrimidinium: the role of solvation.

The p K(a)'s of the 6-CH groups of N-methyl-2-methoxypyridinium, N-methyl-4-methoxypyridinium, and 1-methyl-2,4-dimethoxypyrimidinium ions in aqueous solution were determined to be about 33. The p K(a) values were nearly identical to each other and surprisingly similar to those reported for the neutral pyridones and uracil. Further determination of the enthalpies and entropies of the H-D exchange reactions revealed the role of solvation.