Divergent Asymmetric Total Synthesis of (+)-Panduratin I, (+)-Nicolaioidesin B, (+)-Isopanduratin A1, and (+)-2-Hydroxyisopanduratin A via Enantioselective Radical Cation (4 + 2) Cycloaddition

The first asymmetric total synthesis of panduratin I, nicolaioidesin B, isopanduratin A1, and 2-hydroxyisopanduratin A has been achieved. The characteristic chiral cyclohexenyl skeleton of these natural products was constructed via enantioselective radical cation (4 + 2) cycloaddition using chiral iron(III) photoredox catalysis. Subsequent transformations provided a versatile intermediate for the divergent synthesis of all four natural products.