Direct catalytic asymmetric synthesis of highly functionalized tetronic acids/tetrahydro-isobenzofuran-1,5-diones via combination of cascade three-component reductive alkylations and Michael-aldol reactions

A practical and sustainable chemical process for the synthesis of highly substituted tetrahydro-isobenzoluran-1,5-diones was achieved for the first time through asymmetric cascade Michael-aldol reaction of 4-hydroxy-3-alkyl-5H-furan-2-ones with alkyl vinyl ketones in the presence of a catalytic amount of L-proline or 9-amino-9-deoxyepiquinine/TCA. In this article, we discovered for the first time the asymmetric synthesis of privileged bicyclic lactones through kinetic resolution and show the synthetic application to pharmaceuticals and natural products synthesis.