Gold(I)-catalyzed hydration reactions of diynes to access tetrasubstituted cyclohexenones

Tetrasubstituted 2-carboalkoxy-3-substituted-cyclohexenones are powerful building blocks for the synthesis of a variety of bioactive target molecules. Their preparations requires multi-steps sequence involving the use of stoichiometric quantities of various reagents, while the catalytic approaches are limitited to trisubstituted cyclohexenones. We describe here an efficient catalytic approach based on gold(I)-catalysis starting from unsymmetrical diynyl mono-ester or symmetrical diynyl di-ester substrates. The carbon chain linking the two alkyne functions can bear two or one substituent, or even be unsubstituted. Regardless of the nature of the substrates and independently of its substitution, the cyclohexenone derivatives are cleanly produced.