Collective Synthesis of Natural Products Sharing the Dihydro‐γ‐Ionone Core

We decided to follow the so‐called “collective total synthesis” approach to synthesize several structurally different molecules from a common intermediate possessing appropriate stereochemistry and functionalities. As the common precursor for the efficient preparation of these bioactive molecules, we chose (+)‐3,4‐dihydro‐γ‐ionone ( 1 ), a natural compound present in minor quantities in ambergris and in the plant Bellardia trixago . Thus, we report herein the enantioselective synthesis of siccanochromene F ( 2 ), metachromins U ( 3 ) and V ( 4 ), and bicyclic squalene derivative 5 as well as the formal syntheses of ambrein ( 6 ), phenazinomycin ( 7 ), and (–)‐siccanin ( 8 ).