Facile Access to Optically Active Labdane-Type Diterpenes from (+)-Manool. Synthesis of (+)-Coronarin E, (+)-15,16-Epoxy-8(17),13(16),14-labdatriene, and (+)-Labda-8(17),13(Z)-diene-15,16-diol

An efficient method for the synthesis of (+)-coronarin E (1), (+)-15,16-epoxy-8(17),13(16),14-labdatriene (2), and (+)-labda-8(17),13(Z)-diene-15,16-diol (3) from (+)-manool is described.