Abstract A mild synthetic approach was established allowing for a convenient construction of tricyclic hydroxyphenanthraquinones, the key precursor for total synthesis of tanshinone I. This tandem process includes decarboxylative radical alkylation, intramolecular C–H arylation and one-pot O-demethylation and aromatization. Variously substituted phenylpropanoic acids were well tolerated in this approach, and synthesis of tanshinone I ...