syn-Diastereoselective glycolate aldol addition reactions of an N(3)-(p-methoxyphenoxy)acetyloxazolidine-2-thione

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• 作者：Craig S. Haynes ; Cassie A. Goodman ; Juandah Bruce ; Sarah C. Genin ; Brad J. Austermuehle ; Victor L. Leong ; Austin R. Leise ; Robert Larson ; Christopher G. Hamaker ; Shawn R. Hitchcock ; ^{hitchcock@ilstu.edu}
• 刊名：Tetrahedron: Asymmetry
• 出版年：2017
• 出版时间：15 January 2017
• 年：2017
• 卷：28
• 期：1
• 页码：98-104
• 全文大小：916 K
• 卷排序：28

文摘

An N3-(p-methoxyphenoxy)acetyloxazolidine-2-thione has been synthesized and employed in glycolate asymmetric aldol addition reactions with aromatic and aliphatic aldehydes. It was determined that the titanium tetrachloride medicated aldol reaction afforded diastereoselectivities that ranged from 75:25 to 94:6 when the reaction was conducted at −78 °C. The absolute stereochemistry of the aldol adducts was determined by 1H NMR spectroscopy and X-ray crystallography. The 1H NMR spectra of the aldol adducts contained a signal (the α-proton of the glycolate position of the aldol side chain) that was highly deshielded due to conformational restriction about the N(3)-(p-methoxyphenoxy)acetyl side chain and the oxazolidine-2-thione auxiliary.