Total synthesis of (±)-nitidanin and novel procedures for determination of the location of the side chains on 1,4-benzodioxane

Regioselective cycloaddition of o-quinone 4 and protected sinapyl alcohol 2 gave 1,4-benzodioxane 5, which was converted to (±)-nitidanin (6), an antimalarial compound. Two novel procedures were developed to determine the location of the side chains of the adduct (5) based on partial ring cleavage.