Chloroform as a Hydrogen Atom Donor in Barton Reductive Decarboxylation Reactions

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• 作者：Junming Ho ; Jingjing Zheng ; Rub茅n Meana-Pa帽eda ; Donald G. Truhlar ; Eun Jung Ko ; G. Paul Savage ; Craig M. Williams ; Michelle L. Coote ; John Tsanaktsidis
• 刊名：The Journal of Organic Chemistry
• 出版年：2013
• 出版时间：July 5, 2013
• 年：2013
• 卷：78
• 期：13
• 页码：6677-6687
• 全文大小：417K
• 年卷期：v.78,no.13(July 5, 2013)
• ISSN：1520-6904

文摘

The utility of chloroform as both a solvent and a hydrogen atom donor in Barton reductive decarboxylation of a range of carboxylic acids was recently demonstrated (Ko, E. J. et al. Org. Lett. 2011, 13, 1944). In the present work, a combination of electronic structure calculations, direct dynamics calculations, and experimental studies was carried out to investigate how chloroform acts as a hydrogen atom donor in Barton reductive decarboxylations and to determine the scope of this process. The results from this study show that hydrogen atom transfer from chloroform occurs directly under kinetic control and is aided by a combination of polar effects and quantum mechanical tunneling. Chloroform acts as an effective hydrogen atom donor for primary, secondary, and tertiary alkyl radicals, although significant chlorination was also observed with unstrained tertiary carboxylic acids.