伪- and 伪鈥?Lithiation鈥揈lectrophile Trapping of N-Thiopivaloyl and N-tert-Butoxythiocarbonyl 伪-Substituted Azetidines: Rationalization of the Regiodivergence Using NMR and Computati

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• 作者：Kelvin E. Jackson ; Claire L. Mortimer ; Barbara Odell ; Jeffrey M. McKenna ; Timothy D. W. Claridge ; Robert S. Paton ; David M. Hodgson
• 刊名：Journal of Organic Chemistry
• 出版年：2015
• 出版时间：October 16, 2015
• 年：2015
• 卷：80
• 期：20
• 页码：9838-9846
• 全文大小：475K
• ISSN：1520-6904

文摘

¹H NMR and computational analyses provide insight into the regiodivergent (伪- and 伪鈥?) lithiation鈥揺lectrophile trapping of N-thiopivaloyl- and N-(tert-butoxythiocarbonyl)-伪-alkylazetidines. The magnitudes of the rotation barriers in these azetidines indicate that rotamer interconversions do not occur at the temperature and on the time scale of the lithiations. The NMR and computational studies support the origin of regioselectivity as being thiocarbonyl-directed lithiation from the lowest energy amide-like rotameric forms (cis for N-thiopivaloyl and trans for N-tert-butoxythiocarbonyl).