Sulfoxide-Based Enantioselective Nazarov Cyclization: Divergent Syntheses of (+)-IsopaucifloralF, (+)-QuadrangularinA, and (+)-Pallidol

The synthesis of enantiomerically pure 3-aryl substituted indanones is developed using an enantioselective sulfoxide-based Knoevenagel condensation/Nazarov cyclization procedure. After the reductive desulfonation of the methyl para-tolyl sulfoxide-containing chiral auxiliary under mild conditions, selected enantiomerically pure indanone is used for the divergent total syntheses of three resveratrol natural products (+)-isopaucifloralF, (+)-quadrangularinA, and (+)-pallidol.