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

A catalytic enantioselective vinylogous domino reaction has been achieved from ketone-derived benzylidene Meldrum's acid and alpha-ketolactones to provide spirolactone dihydropyranones with more than 99% ee. An Auto Tandem Catalysis (ATC) process resulting from dual and complementary role of (DHQ)(2)PHAL 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.

Automated summary

A catalytic enantioselective vinylogous domino reaction has been successfully achieved, providing spirolactone dihydropyranones with high enantiomeric excess. The reaction involves an Auto Tandem Catalysis (ATC) process facilitated by the dual and complementary role of (DHQ)(2)PHAL organocatalyst, leading to good yields and high selectivity.