Construction of 5-Amino-1,2-Selenazole Scaffolds through N-Selenocyanation/Cyclization of Enaminones Using KSeCN.

A metal-free and mild approach for constructing 5-amino-1,2-selenazole skeletons by NBS/KSeCN-mediated N-selenocyanation and nucleophilic cyclization of ß-enaminones has been developed. Various isoselenazole compounds and the isoselenazolyl derivatives of anti-inflammatory medicines, including isosepac, oxaprozin, and ibuprofen, have been obtained with good yields. This efficient, "one-pot", and atomic economy strategy may represent an alternative route for the construction of a 1,2-selenazole framework via the "+SeCN" pathway and provide new access to heterocycles containing a Se-N bond.

Molybdenum(V)-mediated switching of the C(sp2)-Se bond of phenylselenyl-functionalized arenes or heterocycles under mild conditions.

Molybdenum(V)-mediated cleavage of C(sp2)-Se bond and C(sp2)-H bond as well as intramolecular oxidative C(sp2)-Se coupling reaction of phenylselenyl-functionalized arenes or heterocycles has been developed. Three kinds of benzoselenophene frameworks were constructed through this reaction with yields up to 94%. This new C(sp2)-Se bond-switching methodology may provide a new strategy for interesting applications of phenylselenyl-substituted aromatic compounds in the synthesis of selenium-containing heterocycles and natural products.