Direct Nitration of Vinylcycles with Copper Nitrate.

A direct nitration of vinylcyclopropanes is disclosed with Cu(NO3)2 and KI in a regio- and stereoselective manner to afford nitroalkenes efficiently, where the cyclopropane skeleton was retained. The given method could be extended to other vinylcycles as well as biomolecule derivatives with wide substrate scope, good functionality tolerance, and efficient synthesis modularity. Further transformations illustrated the obtained products as versatile building blocks in organic synthesis. The proposed ionic pathway could account for the untouched small ring and the effect of KI during the reaction.