Asymmetric Total Syntheses of (+)-Asperterpenoids D and E with a Concurrent Synthesis of ent -(−)-Homoverrucosanol

The first asymmetric total syntheses of sesterterpenoids (+)-asperterpenoids D and E, together with a concurrent synthesis of diterpenoid ent-(−)-homoverrucosanol were achieved from (S)-limonene through a chiral-pool strategy featuring a common late-stage intermediate. Key transformations include a Michael addition and a highly diastereoselective Type I [5 + 2] cycloaddition, which successively establish the C-14 and C-11 methyl-bearing stereocenters with complete stereocontrol. Subsequent oxa-bridge cleavage, cyclopropanation, and A-ring formation via hydroformylation and Carreira cyclopentenal synthesis proceed stereospecifically.