Organocatalytic asymmetric domino Knoevenagel/Diels-Alder reactions: A bioorganic approach to the diastereospecific and enantioselective construction of highly substituted spiro [5,5]undecane-1,5,9-triones

Abstract

A practical and environmentally friendly organocatalytic process for the synthesis of optically active highly substituted spiro[5,5]undecane-1,5,9-triones was achieved through the reaction of an aldehyde, an enone, and Meldrum's acid in the presence of a catalytic amount of chiral amino acid (see scheme). The Diels-Alder products were obtained as single diastereomers in excellent yields and enantiomeric excesses.