We describe a convergent, enantioselective synthesis of (-)-tetracycline (1) from benzoic acid (17 steps, 1.1% yield). Benzoic acid was transformed into the AB precursor 2 in 10 steps (11% yield), as previously described, and the latter compound was activated toward Diels-Alder cycloaddition by the introduction of an α-phenylthio group (two steps, 66% yield). Heating of the resulting α-(phenylthio) enone (3) with the triethylsilyloxybenzocyclobutene ...
