Stereo-controlled Alkylation of Cyclodecadienone Derivatives and the Total Synthesis of (-)- and (+)-4,5-cis-3β-Hydroxygermacranolides

Article abstract of DOI:10.1246/cl.1986.1879

Direct trapping of the intermediate, produced by anionic oxy-Cope rearrangement of (1S,4S,6S)-4-alkoxy-1-ethenyl-3-methyl-6-(1-methylethenyl)-2-cyclohexen-1-ol, with ethyl bromoacetate gave ethyl <3S,7S,1(10)E,4Z>-3-alkoxy-6-oxo-13-nor-1(10),4-germacradien-12-oate stereoselectively, which was converted into a natural (-)-4,5-cis-3β-hydroxygermacranolide.