Magnesium Ethoxide Promoted Conversion of Nitriles to Amidines and Its Application in 5,6-Dihydroimidazobenzoxazepine Synthesis.

Magnesium ethoxide has been shown to be a mild, safe, and scalable alternative to trimethylaluminum for the direct addition of amines to aryl nitriles to access cyclic amidines. A variety of electronically diverse oxa-, thia-, and diazepine products were successfully synthesized in moderate to high yields. Further elaboration of these compounds to 5,6-dihydroimidazobenzoxazepines, a privileged class of pharmacologically active heterocycles, highlights the utility of this method.

Synthesis of the pentacyclic skeleton of the indole alkaloid arboflorine.

An effective synthesis of the pentacyclic core of the unusual Kopsia alkaloid arboflorine is reported. The success of the synthetic route rested on the use of a borylative C-H functionalization reaction, a convergent Suzuki cross-coupling to a C(2) halogenated indole, and an unprecedented transannular dehydrogenative C-N bond forming reaction.