Axially chiral hemiaminals from nonracemic α‐amino acid derivatives (thiohydantoins): Synthesis and isomer identification
作者:Sevgi Sarigul Ozbek、Ilknur Dogan
DOI:10.1002/chir.23274
日期:2020.11
Stable, nonracemic axially chiral hemiaminals (O,N‐hemiacetals) have been synthesized stereoselectively from lithium aluminum hydride (LiAlH4) reductions of nonracemic 5‐methyl‐ and 5‐isopropyl‐3‐(o‐aryl)‐2‐thioydantoins in tetrahydrofuran (THF) at room temperature in 10 min. Predominantly S‐configured hemiaminals at C‐4 of the heterocyclic ring were produced from the S‐configured thiohydantoins at
稳定,非外消旋的轴向手性缩醛(O,N-半缩醛)是由氢化锂铝(LiAlH 4)立体选择性合成的,由四氢呋喃中的非外消旋的5-甲基和5-异丙基-3-(邻芳基)-2-硫代乙二醛还原而成。 (THF)在室温下放置10分钟。杂环C-4处主要由S-构型的血醛糖类由C-5处的S-构型乙内酰脲产生(C5取代基为甲基时为80%,异丙基为97%)。在还原反应过程中保留了C-5的构型。轴向手性hemiaminals的立体化学结果是由于它们的构象偏好所致。