A facile and practical method of preparing optically active α-monosubstituted cycloalkanones by thermodynamically controlled deracemization

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• 作者：Hiroto Kaku ; Aya Nakamaru ; Makoto Inai ; Takeshi Nishii ; Mitsuyo Horikawa ; Tetsuto Tsunoda
• 关键词：Deracemization ; Molecular recognition ; Host– ; guest chemistry ; Inclusion complexation ; Optically active cycloalkanones
• 刊名：Tetrahedron
• 出版年：2010
• 出版时间：27 November 2010
• 年：2010
• 卷：66
• 期：48
• 页码：9450-9455
• 全文大小：820 K

文摘

Racemic 2-monosubstituted cycloalkanones were converted to R-isomers when TADDOLs (e.g., 1a, b) were used as host molecules in alkaline aqueous MeOH. The efficiency of this thermodynamically controlled deracemization was strongly influenced by the mixture ratio of the solvent, H₂O/MeOH. Based on this finding, an improved method of preparing (R)-2-monosubstituted cycloalkanones with higher optical purity was developed. For example, (R)-2-(4-methylbenzyl)cyclohexanone (5) was obtained in 85 % yield with 98 % ee, when a 1:1 mixture of H₂O/MeOH was used as the solvent in the presence of 1a.