Anthracyclines, synthesis

Kimura, Y, Suzuki, M, Matsumoto, T, Ahe, R, Terashima, S, Trimethylsilyl trifluoromethanesulfonate (trimethylsilyl triflate) as an excellent glycosidation reagent for anthracycline synthesis. Simple and efficient synthesis of optically pure 4-demethoxydaunoruhicin, Chem. Lett, 501 -504, 1984. 

Serving as the key step for an anthracycline synthesis, addition of the epoxytetrone dienophile (452) to diene (451) gave a mixture of adducts (453) and (454) in ratios of 4 1 (CsHe, 5 C) up to 7 1 (acetone, 5 °C) (Scheme 107). The major isomer (453), isolated by crystallization (74% yield from 451), was then converted into (+)-4-deme oxydaunomycinone (641) (Scheme 142) via glycoside cleavage with 0.5N... 

For our anthracycline synthesis, the anionic cycloaddition reaction of the homophthalic anhydrides and quinone dienophiles, leading to the aglycone skeletons of anthracyclines, plays a key role. Table 1 shows the results of the cycloaddition reactions of the homophthaUc anhydrides with quinone... 

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