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Pure Appl. Chem., 2004, Vol. 76, No. 3, pp. 495-505

Application of allylic substitutions in natural products synthesis

G. Helmchen, Martin Ernst and G. Paradies

Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany

Abstract: Synthesis routes are described, allowing all known jasmonoids as well as their enantiomers to be synthesized in enantiomerically and diastereomerically pure form. The routes are based on a set of closely related lactones containing an electrophilic allylic moiety, which are accessible via asymmetric Pd-catalyzed allylic alkylation. Regio- and diastereoselective SN2'-anti-reactions of the electrophilic lactones with organocopper compounds furnished 2,3-cis-disubstituted cyclopentenones, which were further transformed into the target compounds, i.e., 12-oxophytodienoic acid (12-OPDA) in excellent overall yields. The methodology also allowed iridoids and isoprostanes to be prepared. The configuration of an Archaea membrane lipid constituent containing cyclopentane rings was determined by total synthesis of a diol that was also obtained by degradation of the natural product.