First enantioselective synthesis of (-)- and (+)-virgatusin, tetra-substituted tetrahydrofuran lignan.

The first highly enantioselective syntheses of tetra-substituted tetrahydrofuran lignan, (-)- and (+)-virgatusin, were achieved. Hemiacetal was stereoselectively obtained from Evans's syn-aldol product as a single isomer. This hemiacetal was converted to (-)-virgatusin via hydrogenolysis. (+)-Virgatusin was also synthesized through the same process. The enantiomeric excess of the both enantiomers was determined as more than 99% ee.