Polarity-Reversible Conjugate Addition Tuned by Remote Electronic Effects

A new concept, polarity-reversible conjugate addition, has been described, based on the findings that the polarity of a classical Michael acceptor can be reversed through remote electronic effects. In addition, the remote electronic effects are tunable, and both five- and six-membered nitrogen rings can be constructed starting from acyclic precursors having the same enone structure unit simply by varying a remote substituent in the molecules.