Total Synthesis of (−)-Rhodomollanol A

An asymmetric approach for the first total synthesis of (−)-rhodomollanol A, a highly oxidized diterpenoid, is described. The efficient synthetic strategy features three key transformations: (1) an oxidative dearomatization-induced (5 + 2) cycloaddition/pinacol-type 1,2-acyl migration cascade to build up the bicyclo­[3.2.1]­octane skeleton; (2) a retro-Dieckmann fragmentation/vinylogous Dieckmann cyclization cascade to assemble the bicyclo­[3.3.0]­octane subunit; and (3) a photo-Nazarov cyclization/intramolecular cycloetherification cascade to forge the 7-oxabicyclo­[4.2.1]­nonane core structure of the natural product.