acid was found to be cleanly resolved by forming a salt with (−)-N-methylephedrine, furnishing optically pure (R)-carboxylic acid. Successive treatments of the (R)-carboxylic acid with N,N′-carbonyldiimidazole and methylmagnesium bromide in the presence of trimethylsilyl triflate readily produced optically pure (R)-(−)-7-deoxy-4-demethoxydaunomycinone, the key synthetic intermediate of (+)-4-demethoxydaunomycinone
发现 2-
氯-
1,3-丁二烯与
蒽-1,4,9,10-
四氢呋喃的狄尔斯-阿尔德反应仅发生在外部 (C2,3) 双键上,从而以极好的收率得到加合物。将加合物加工成 5,12-二羟基-1,2,3,4-四氢-2,6,11-
萘三酮。该样品的常规
氰醇形成随后酸
水解得到(±)-2,5,12-三羟基-6,11-二氧-
1,2,3,4-四氢-2-萘甲酸。通过与 (-)-
N-甲基麻黄碱形成盐,发现外消旋酸被彻底拆分,提供光学纯的 (R)-
羧酸。在
三氟甲磺酸三甲基甲
硅烷基酯的存在下,用
N,N'-羰基二咪唑和
甲基溴化镁连续处理 (R)-
羧酸很容易产生光学纯的 (R)-(-)-7-脱氧-4-脱甲氧基
道诺霉素酮,