Probing the Efficiency of N-Heterocyclic Carbene Promoted O- to C-Carboxyl Transfer of Oxazolyl Carbonates
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- 作者：Jennifer E. Thomson ; Craig D. Campbell ; Carmen Concelló ; n ; Nicolas Duguet ; Kathryn Rix ; Alexandra M. Z. Slawin ; Andrew D. Smith
- 刊名：Journal of Organic Chemistry
- 出版年：2008
- 出版时间：April 4, 2008
- 年：2008
- 卷：73
- 期：7
- 页码：2784 - 2791
- 全文大小：174K
- 年卷期：v.73,no.7(April 4, 2008)
- ISSN：1520-6904
文摘
Screening of a range of azolium salts, bases and solvents for reactivity indicates that triazolinylidenes,generated in situ with KHMDS in THF, promote the Steglich rearrangement of oxazolyl carbonates withhigh catalytic efficiency (typical reaction time 5 min at <1.5 mol % NHC). This protocol shows widesubstrate applicability, even allowing the efficient generation of vicinal quaternary centers. An improvedexperimental procedure is also described that allows a simplified one-pot reaction protocol to be employedwith similarly high catalytic efficiency.