Science of Synthesis

Marsden, S. P., Science of Synthesis, (2005) 26, 1045.

The chemistry of α,β-unsaturated ketones is diverse and widespread throughout organic chemistry. Amongst the diverse reactions of enones, their ambident electrophilicity is most widely studied. Addition of hard nucleophiles to the ketone function is complemented by their ability to act as Michael acceptors of softer heteroatoms and stabilized and nonstabilized carbanion nucleophiles (and radicals). The reaction of both electrophilic sites with double nucleophiles is particularly useful in the synthesis of five-membered heterocycles. The alkene portion of the enone can participate as a 2π-component in [2+2], [3+2], and [4+2] cycloadditions (both thermal and photochemical), whereas the entire moiety can act as a heterodiene for Diels–Alder cycloadditions. The vast range of chemistry which can be effected upon the functional group and the potential diversity in structure of the products have stimulated the development of numerous methods for the preparation of such enones.