Stereochemistry in Nucleophilic Vinylic Substitution of Activated Nitro Olefins

Each of E and Z-isomers of activated α,β-dinitro olefins and α-iodo-β-nitrostilbene reacted ith several different types of nucleophiles such as amines, thiocyanate, and p-toluenethiolate. Only Z-isomers of vinylic-substituted olefins with amines and thiocyanate were observed as products due to the attractive interactions between the nitro group of substrate and the nucleophile in the intermediate state. p-Toluenethiolate as a nucleophile could not interact strongly enough to yield a single Z-product but a converged (E) and (Z) mixture of products. Still, preference is toward Z-configuration.