A short synthesis of the anti-leukemic sesquiterpene (+)-caparratriene employing aqueous Wittig chemistry

An efficient, stereoselective method for the synthesis of (+)-caparratriene based on an aqueous Wittig reaction has been developed. A functionalized triethylallyl ylide reacted under various conditions with (+)-citronellal to deliver (+)-caparratriene in only three steps with excellent overall yield. The Wittig reaction proceeded with exclusive (4E)-selectivity and an interesting cationic effect was uncovered with good stereoselectivity at the isomerizable allylic position being observed in the presence of lithium salts. (C) 2010 Elsevier Ltd. All rights reserved.