Catalytic and Stoichiometric Cumulene Formation within Dimeric Group 2 Acetylides

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• 作者：Merle Arrowsmith ; Mark R. Crimmin ; Michael S. Hill ; Sarah L. Lomas ; Dugald J. MacDougall ; Mary F. Mahon
• 刊名：Organometallics
• 出版年：2013
• 出版时间：September 9, 2013
• 年：2013
• 卷：32
• 期：17
• 页码：4961-4972
• 全文大小：525K
• 年卷期：v.32,no.17(September 9, 2013)
• ISSN：1520-6041

文摘

A series of 尾-diketiminate-supported magnesium and calcium acetylide complexes have been synthesized by 蟽-bond metathesis of magnesium n-butyl or magnesium and calcium amido precursors and a range of terminal acetylenes. The dimeric complexes have been characterized by NMR spectroscopy and X-ray diffraction analysis. The homoleptic bis(amido) and dialkyl complexes [M{X(SiMe₃)₂}₂(THF)₂] (M = Ca, Sr; X = N, CH) have been assessed for the atom-efficient, catalytic head-to-head dimerization of donor-functionalized terminal alkynes into butatrienes and aryl-/silyl-substituted terminal acetylenes into 1,3-enynes. Deuterium labeling studies of the catalytic reactions are suggested to imply that triene formation requires concerted proton delivery and rearrangement via an adjacent methylene group at a bimetallic alkaline-earth species.