Asymmetric Total Syntheses of Insulicolide A, 14- O-Acetylinsulicolide A, 6β,9α-Dihydroxy-14- p-nitrobenzoylcinnamolide, and 7α,14-Dihydroxy-6β- p-nitrobenzoylconfertifolin.

Asymmetric total syntheses of insulicolide A, 14- O-acetylinsulicolide A, 6β,9α-dihydroxy-14- p-nitrobenzoyl cinnamolide, and 7α,14-dihydroxy-6β- p-nitrobenzoylconfertifolin have been achieved for the first time. The key steps in the synthesis include: (1) an iridium-catalyzed enantioselective polyene cyclization to construct the drimane core bearing two all-carbon quaternary chiral centers at C4 and C10 and (2) a cascade ozonolysis of the phenol ring to form the lactone fragment of the target molecules.