Shuang Ma

The use of a halogen bond donor to catalyze Friedel-Crafts reactions of indoles with a range of aldehydes and ketones to directly produce bis(indolyl)methanes, including the natural products arsindoline A, arundine, trisindoline, and vibrindole A, is reported. The bidentate catalyst used in these reactions proved to be more effective than a monondentate analogue, a thiourea commonly used as an organocatalyst, and even a trityl cation that has been used previously in the synthesis of bis(indolyl)methanes.

A simple and efficient copper-catalyzed one-pot synthesis of substituted 1,2,4-triazoles through reactions of two nitriles with hydroxylamine has been developed. The protocol uses simple and readily available nitriles and hydroxylamine hydrochloride as the starting materials and inexpensive Cu(OAc)2 as the catalyst, and the corresponding 1,2,4-triazole derivatives are obtained in moderate to good yields. The reactions include sequential intermolecular addition of hydroxylamine to one nitrile to provide amidoxime, copper-catalyzed treatment of the amidoxime with another nitrile, and intramolecular dehydration/cyclization. This finding provides a new and useful strategy for synthesis of 1,2,4-triazole derivatives.