The first total syntheses of tetracenomycins C and X were achieved, featuring 1) preparation of a hexasubstituted naphthonitrile oxide by successive benzyne cycloadditions and an oxidative ring-opening reaction; 2) a novel ortho-quinone mono-acetal as the A-ring unit; 3) construction of three contiguous stereogenic centers by an asymmetric benzoin cyclization, an isoxazole oxidation, and a stereoselective reduction.

The first total syntheses of tetracenomycins Cand X were achieved,f eaturing 1) preparation of ah exasubstituted naphthonitrile oxide by successive benzyne cycloadditions and an oxidative ring-opening reaction;2 )a novel ortho-quinone mono-acetal as the A-ring unit;3 )construction of three contiguous stereogenic centers by an asymmetric benzoin cyclization, an isoxazole oxidation, and as tereoselective reduction.