Abstract The vinylogous β-keto esters, ethyl 2-methyl-4-oxocyclohex-2-ene-carboxylate (Hagemann's Ester)(4), ethyl 4-oxocyclohex-1-ene-carboxylate (7a) and its double bond isomer (7b), undergo regiospecific arylation with aryllead triacetates at C1; reaction of the mixture of isomers (7a) and (7b) with aryllead compounds (5a),(5c) and (5d) provides intermediates for the synthesis of (±)-o-methyl-joubertiamine (1),(±)-mesembrine (2) and ( ...
