A process for the enantioselective synthesis of an (S)— or (R)-1-[2-dimethylamino)-1-(methoxyphenyl)ethyl]cyclohexanol and analogues or salt thereof are described. The method involves the steps of (a) reacting an (S) or (R) 4-benzyloxazolidinone with a mixed anhydride of a methyoxyphenylacetic acid under conditions which form a oxazolidinone, (4S)— or (4R)-4-benzyl-3-[methyoxyphenyl]acetyl]-oxazolidin-2-one, (b) treating the (4S)— or (4R)-4-benzyl-3-[(methoxyphenyl)acetyl]-1,3-oxazolidin-2-one with an aprotic amine base and titanium chloride in a chlorinated solvent under conditions which permit formation of the corresponding anion, (c) mixing the corresponding anion with titanium chloride and cylcohexanone under conditions which permit an aldol reaction to form the corresponding (4S)— or (4R)-4-benzyl-3-[(2R)-2-(1-hydroxycyclohexyl)-2-(methoxyphenyl)acetyl]-1,3-oxazolidin-2-one, (d) hydrolyzing the (4S)— or (4R)-4-benzyl-3-[(2R)-2-(1-hydroxycyclohexyl)-2-(methoxyphenyl)acetyl]-1,3-oxazolidin-2-one to form a chiral acid (2S or 2R)-(1-hydroxycyclohexyl)-methoxyphenyl)acetic acid, (e) coupling the chiral phenylacid to a secondary amine to form an amide, and (f) reducing the amide to form an (S) or (R) 1[2-dimethylamino)-1-(methoxyphenyl)ethyl]cyclohexanol or a salt thereof.
描述了一种对(S)-或(R)-1-[2-
二甲氨基)-1-(
甲氧基苯基)乙基]
环己醇及类似物或其盐进行对映选择性合成的过程。该方法涉及以下步骤:(a)在形成氧杂
环己酮的条件下,将(S)或(R) 4-苄氧环丙
氨酮与
甲氧基苯乙酸混合酐反应,形成(4S)-或(4R)-4-苄基-3-[
甲氧基苯基]乙酰氧杂环
丙酮;(b)在
氯化溶剂中,用无
水胺碱和
氯化
钛处理(4S)-或(4R)-4-苄基-3-[(
甲氧基苯基)乙酰]-1,3-氧杂环
丙酮,使其形成相应的负离子;(c)将相应的负离子与
氯化
钛和
环己酮混合,在醛醇反应条件下形成相应的(4S)-或(4R)-4-苄基-3-[(2R)-2-(1-羟基环己基)-2-(
甲氧基苯基)乙酰]-1,3-氧杂环
丙酮;(d)
水解(4S)-或(4R)-4-苄基-3-[(2R)-2-(1-羟基环己基)-2-(
甲氧基苯基)乙酰]-1,3-氧杂环
丙酮,形成手性酸(2S或2R)-(1-羟基环己基)-
甲氧基苯乙酸;(e)将手性苯酸与二级胺偶联形成酰胺;(f)还原酰胺形成(S)或(R) 1-[2-
二甲氨基)-1-(
甲氧基苯基)乙基]
环己醇或其盐。