The Use of Ureates as Activators for Samarium Diiodide

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• 作者：Chriss E. McDonald ; Jeremy D. Ramsey ; Christopher C. McAtee ; Joseph R. Mauck ; Erin M. Hale ; Justin A. Cumens
• 刊名：Journal of Organic Chemistry
• 出版年：2016
• 出版时间：July 15, 2016
• 年：2016
• 卷：81
• 期：14
• 页码：5903-5914
• 全文大小：606K
• 年卷期：0
• ISSN：1520-6904

文摘

A novel mode of SmI₂ activation has been developed using ureates as reaction promoters. Several ureates formed by treatment of the corresponding ureas with n-BuLi have been shown to activate SmI₂ to a substantial extent toward the reduction of 1-chlorodecane. Complexes formed from SmI₂ and various ureates have been shown to be useful for the reduction of a variety of organohalides, including substrates of low reactivity such as aryl fluorides. Because of ease of synthesis and low molecular weight, the conjugate base of triethylurea (TEU^–) was of primary focus. Visible spectroscopy and reactivity data are consistent with the hypothesis that the same complex is being formed when SmI₂ is combined with either 2 or 4 equiv of TEU^–, in spite of the greater reactivity of SmI₂/4 TEU^– with some alkyl halides. We propose that the active reductant is an N,O chelate formed between SmI₂ and 2 equiv of TEU^–.