Protoilludane sesquiterpenes: synthesis of (+/-)-cerapicol, formal synthesis of (+/-)-sterpurene, and synthesis and absolute configuration of (+)-cerapicol

New approaches to the protoilludane sesquiterpenes (+/-)-cerapicol and (+/-)-sterpurene via rearrangement routes are described. The absolute configuration of (+)-cerapicol has been determined and found in accord with a biosynthesis of the natural product via cyclization of humulene to the so-called protoilludyl cation and a subsequent 1,2-alkyl shift. (C) 2008 Elsevier Ltd. All rights reserved.