Deuterium as a Stereochemically Invisible Blocking Group for Chiral Ligand Synthesis
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- 作者：Ross A. Arthurs ; Christopher J. Richards
- 刊名：Organic Letters
- 出版年：2017
- 出版时间：February 3, 2017
- 年：2017
- 卷：19
- 期：3
- 页码：702-705
- 全文大小：370K
- ISSN：1523-7052
文摘
Highly diastereoselective lithiation (s-BuLi/TMEDA in Et2O, −78 °C, 2 h) of (S)-2-ferrocenyl-4-(substituted)oxazolines followed by addition of MeOH-d4 gave up to 95% D incorporation. Subsequent application of alternative lithiation conditions (n-BuLi in THF, −78 °C, 2 h), followed by addition of an electrophile, resulted in a reversal of diastereoselectivity controlled primarily by the high kH/kD value for lithiation (isomer ratio typically between 10:1 and 20:1).