Synthesis of Cordiaquinones B, C, J, and K on the Basis of a Bioinspired Approach and the Revision of the Relative Stereochemistry of Cordiaquinone C

2008-06-20T00:00:00Z (GMT) by Elias Arkoudis Manolis Stratakis
Four members of the cordiaquinone family (cordiaquinones B, C, J, and K) were synthesized on the basis of a bioinspired scenario in five to six steps from <i>trans</i>,<i>trans</i>-farnesol. As key reactions we used the acid-catalyzed cyclization of a suitable epoxy terpenoid and a Diels−Alder reaction between a diene and benzoquinone. The relative stereochemistry of cordiaquinone C is opposite to that reported in the isolation paper and is in agreement with a plausible scenario for the biosynthesis of cordiaquinones from a common (<i>E</i>)-configurated naphthoquinone epoxide precursor. A fast and clean methodology for the synthesis of the naturally occurring (<i>Z</i>)-β-farnesene from <i>cis</i>-nerolidol is also reported.