Cyclisation of terpenylnaphthohydroquinone derivatives or terpenylquinone cycloadducts, obtained from methyl myrcecommunate, was performed in the presence of HI, I-2 or BF3 center dot OEt2 and provides efficient synthetic strategies for the preparation of pentacyclic terpenylquinones. (C) 2011 Elsevier Ltd. All rights reserved.