Synthetic study of aquayamycin. Part 2: Synthesis of the AB ring fragment

A highly oxygen-functionalized cyclohexenone 2, the AB ring fragment for the aquayamycin synthesis, was efficiently synthesized via stereoselective addition of allylzinc bromide to ketone 3a which, in turn, was available from the optically pure cyclohexane 1,2,3-triol derivative 5.