Selective synthesis of multifunctionalized cyclopent-3-ene-1-carboxamides and 2-oxabicyclo[2.2.1]heptane derivatives.

Triethylamine promoted cycloaddition reaction of phenacylmalononitriles and o-hydroxychalcones in ethanol at room temperature gave multifunctionalized cyclopent-3-ene-1-carboxamides in good yields and with high diastereoselectivity. More importantly, the similar reaction of phenacylmalononitriles and chalcone o-enolates in ethanol at room temperature afforded functionalized 2-oxabicyclo[2.2.1]heptane derivatives in satisfactory yields and with high diastereoselectivity. A rational domino reaction was tentatively proposed to explain the selective formation of different cyclic compounds and the diastereoselectivity of the reaction. [ABSTRACT FROM AUTHOR]