Some approaches to the synthesis of tetracycline.

Some approaches to the synthesis of tetracycline are described. Tetracycline [(I), R' = Me, R2 = R3 = H] is a member of the important group of tetracycline antibiotics. Other members of this group of medicinal importance are aureomycin [(I). R' = Me, R2 = H, R3 = Cl], terramycin [(I), R' = Me, R2 = OH, R3 = H] and 6-demethyltetracycline [(I)], R1 = R2 = R3 = H]. All these compounds represent challenging objectives for total synthesis.