Auto Tandem Catalysis: Asymmetric Vinylogous Cycloaddition/Kinetic Resolution Sequence for the Enantioselective Synthesis of Spiro‐Dihydropyranone from Benzylidene Meldrum's Acid

Abstract

AbstractA catalytic enantioselective vinylogous domino reaction has been achieved from ketone‐derived benzylidene Meldrum's acid and α‐ketolactones to provide spirolactone dihydropyranones with more than 99% ee. An Auto Tandem Catalysis (ATC) process resulting from dual and complementary role of (DHQ)2PHAL organocatalyst resulted in a sequence involving an asymmetric vinylogous formal (4+2) cycloaddition of benzylidene and the subsequent kinetic resolution operating through a 1,3‐prototropic shift leading to good yields (>50%) and the high selectivity.magnified image