Stereoselective reduction of (S)-4-isopropyl-3-phenacyl-1,3-oxazolidin-2-one by means of 1,4-asymmetric induction: Synthesis of chiral 2-amino-1-phenylethanols.
作者:HIROSHI TAKAHASHI、NORIYUKI YAMADA、KIMIO HIGASHIYAMA、KENICHI KAWAI
DOI:10.1248/cpb.33.84
日期:——
Stereoselective reductions of (S)-4-isopropyl-3-phenacyl-1, 3-oxazolidin-2-one (2) with several complex metal hydrides gave 2-4'-isopropyl-2'-oxo-1', 3'-oxazolidinyl-1-phenylethanol (3) and 2-N-1'-isopropyl-2'-hydroxyethyl-N-methylamino-1-phenylethanol (4) in good yields. These products were diastereomeric mixtures and the diastereomer ratios were estimated to be ca. 75 : 25. The asymmetric 2-amino-1-phenylethanols (major products of 3 and 4) were easily isolated by recrystallization. The absolute configuration of (1S, 4'S)-3 was determined by X-ray analysis. The reductions of (S)-4-isopropyl-1-phenacyl-1, 3-oxazolidine (6) with complex metal hydrides gave 2-4'-isopropyl-1', 3'-oxazolidinyl-1-phenylethanol (7) and 4 as diastereomeric mixtures (ca. 70 : 30).
(S)-4-异丙基-3-苯乙酰-1,3-氮杂环戊烷-2-酮 (2) 与几种复杂金属氢化物的立体选择性还原反应获得了 2-4'-异丙基-2'-氧基-1',3'-氮杂环戊烷-1-苯乙醇 (3) 和 2-N-1'-异丙基-2'-羟基乙基-N-甲基氨基-1-苯乙醇 (4),产率良好。这些产物为非对映异构体混合物,非对映异构体比率估计为约 75 : 25。非对称 2-氨基-1-苯乙醇(3 和 4 的主要产物)可以通过重结晶轻松分离。通过 X 射线分析确定了 (1S, 4'S)-3 的绝对构型。与复杂金属氢化物还原 (S)-4-异丙基-1-苯乙酰-1,3-氮杂环戊烷 (6) 的反应获得了 2-4'-异丙基-1',3'-氮杂环戊烷-1-苯乙醇 (7) 和 4 作为非对映异构体混合物(约 70 : 30)。