Basidifferquinones, isolated from Streptonzyces sp., are potent inducers for fruiting-body formation of a basidiomycete Polyporus arcularius. Construction of the basic framework of basidifferquinones and the first synthesis of (+/-)-basidifferquinone C were accomplished by starting from 3,5-dihydroxy-2-naphthoic acid. (C) 2008 Elsevier Ltd. All rights reserved.