Divergent Reactivity of D-A Cyclopropanes under PTC Conditions, Ring-Opening vs. Decyanation Reaction

The divergent reactivity of D-A cyclopropane, under PTC conditions, is herein reported. Thus, a ring-opening or a decyanation reaction can be achieved by reacting 2-arylcyclopropane-1,1-dicarbonitriles 1 with thioacetic acid in different reaction conditions. The use of solid Cs2CO3 leads unexpectedly to the synthesis of new D-A cyclopropane derivatives via a decyanation reaction, followed by diastereoselective acetylation, whereas the use of an aqueous solution of Cs2CO3 results in a typical ring-opening reaction with the formation of S-thiolate products. Therefore, the use of tailored reaction conditions allows one to obtain either cyclic or open-chain products in moderate to good yields.