AbstractStarting from ethyl 2‐cyclohexen‐1‐carboxylate (3) the total synthesis of the perhydrohistrionicotoxin intermediate 23 was achieved in 25% overall‐yield. The two key steps involve a positionally specific addition of HOBr to the oxime‐olefin 7 and the alkylation of bromooxime 17 with 1‐lithio‐1‐butyne. The latter represents a novel method for stereospecific and position‐specific introduction of a nucleophilic butyl equivalent in α‐position to a ketonic carbonyl group.
The anodic oxidation of 1-acetoxy-1,6-heptadiene homologues in acetic acid gave mainly intramolecular cyclization products, cyclohexenyl ketones. The cyclization takes place through the electrophilic attack of the cationic center generated from the enol ester moiety to the double bond.