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Axially chiral hemiaminals from nonracemic α‐amino acid derivatives (thiohydantoins): Synthesis and isomer identification
Author(s) -
Sarigul Ozbek Sevgi,
Dogan Ilknur
Publication year - 2020
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.23274
Subject(s) - chemistry , isopropyl , tetrahydrofuran , substituent , aryl , lithium (medication) , stereospecificity , stereochemistry , ring (chemistry) , isopropyl alcohol , medicinal chemistry , organic chemistry , catalysis , alkyl , endocrinology , medicine , solvent
Stable, nonracemic axially chiral hemiaminals ( O , N ‐hemiacetals) have been synthesized stereoselectively from lithium aluminum hydride (LiAlH 4 ) 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 C‐5 (by 80% when the C5 substituent is methyl and by 97% when it is isopropyl). The configuration at C‐5 was retained during the reduction reaction. The stereochemical outcome of the axially chiral hemiaminals resulted from their conformational preferences.