Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... A series of tanshinone-type diterpenoids was prepared by ultrasound-promoted and Lewis acid catalyzed, highly regioselective cycloadditions of styrenes with substituted 1,4-benzoquinones as the key step. ... A series of tanshinone-type diterpenoids was prepared by ultrasound- ...