Synthesis and reactivity of Michael adducts of cyclic β-ketoesters enolates with electrophilic acetylenes

Article abstract of DOI:10.1016/S0040-4039(98)01500-7

The enolates of cyclic β-ketoesters react with electrophilic acetylenes to give the corresponding Michael adducts in good yields when the reaction is performed in acetone in the presence of catalytic amounts of K₂CO₃. The Michael adducts resulting from ethynylmethylketone, when refluxed in toluene in the presence of catalytic amount of pTsOH, undergo an intramolecular aldol reaction leading mainly to bicyclo [n. 3.1]alkadienones besides Robinson annulation products.