One-Pot Knoevenagel and [4 + 2] Cycloaddition as a Platform for Calliviminones

Abstract

Bioactive compounds featuring an unusual core of spiro[5.5]undecenes and calliviminones were synthesized in very good yield with good regio- and diastereoselectivities through a one-pot Knoevenagel and [4 + 2] cycloaddition from the readily available aldehydes, cyclic-1,3-diones, dienes, and a catalytic amount of (s)-proline.