The elemene-type terpenoids, which possess various biological activities, contain a syn- or anti-1,2-dialkenylcyclohexane framework. An efficient synthetic route to the syn- and anti-1,2-dialkenylcyclohexane core and its application in the synthesis of (±)-geijerone and its diastereomer is reported. Construction of the syn- and anti-1,2-dialkenyl moiety was achieved via Ireland-Claisen rearrang...

Total syntheses of (+)-cinereain and (−)-janoxepin, two fungal cyclotripeptides featuring a complex heterocyclic core interesting phytotoxic antimalarial activities, have been achieved in convergent manner. A key step this synthesis is one-pot cascade initiated by the cyclocondensation fragments—a hindered 2-vinylcyclopropane-1-acyl fluoride an electron-deficient cyclic amidine—to release react...

Abstract Various 1‐(1‐hydroxyalkyl) paraconyl alcohols are important signaling molecules within antibiotics production in Streptomyces sp. Intending developing a flexible convergent chemical synthesis of such butanolides, zwitterionic aza‐Claisen rearrangement was chosen as reliable strategy generating the central stereotriad. Reaction enantiopure N ‐allyl pyrrolidines and 4‐phenylbutenoic acid...

The mechanism by which chiral arylpyrrole-substituted guanidinium ions promote the Claisen rearrangement of O-allyl α-ketoesters and induce enantioselectivity was investigated by experimental and computational methods. In addition to stabilization of the developing negative charge on the oxallyl fragment of the rearrangement transition state by hydrogen-bond donation, evidence was obtained for ...