Selective synthesis of (1H-benzo[d]imidazol-2-yl)(phenyl)methanone and quinoxaline from aromatic aldehyde and o-phenylenediamine.

We have designed a general, inexpensive, and versatile method for the synthesis of (1H-benzo[d]imidazol-2-yl)(phenyl)methanone and the formation of C-N bonds via an aromatic aldehyde and o-phenylenediamine. In the presence of N,N-dimethylformamide/sulfur, (1H-benzo[d]imidazol-2-yl)(phenyl)methanone was obtained; however, in the absence of sulfur, quinoxaline was obtained in 1,4-dioxane. A wide range of quinoxalines and (1H-benzo[d]imidazol-2-yl)(phenyl)methanones was obtained under mild conditions.

The synthesis of multi-substituted pyrrolidinones via a direct [3 + 2] cycloaddition of azaoxyallyl cations with aromatic ethylenes.

A novel [3 + 2] cycloaddition reaction of azaoxyallyl cations and aromatic ethylenes has been developed to afford multi-substituted pyrrolidinones in moderate to good yields. This method not only further expands the synthetic utility of α-halo hydroxamates, but also provides an alternative method for the synthesis of bioactive molecules containing pyrrolidinones.