Oxidative Diamination of Alkenes with Ureas as Nitrogen Sources: Mechanistic Pathways in the Presence of a High Oxidation State Palladium Catalyst

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• 作者：Kilian Mu&ntilde ; iz ; Claas H. Hö ; velmann ; Jan Streuff
• 刊名：Journal of the American Chemical Society
• 出版年：2008
• 出版时间：January 16, 2008
• 年：2008
• 卷：130
• 期：2
• 页码：763 - 773
• 全文大小：450K
• 年卷期：v.130,no.2(January 16, 2008)
• ISSN：1520-5126

文摘

A first palladium-catalyzed intramolecular diamination of unfunctionalized terminal alkenes hasrecently been reported. This study investigates the details of its mechanistic course based on NMR titration,kinetic measurements competition experiments, and deuterium labeling. It concludes a two-step procedureconsisting of syn-aminopalladation with an unligated palladium(II) catalyst state followed by oxidation topalladium(IV) and subsequent C-N bond formation to give the final products as cyclic diamines. Relatedreactions employing sulfamides give rise to aminoalkoxy-functionalization of alkenes. This process wasinvestigated employing deuterated alkenes and found to follow an identical mechanism where stereochemistry is concerned. It exemplifies the importance of cationic palladium(IV) intermediates prior to thefinal reductive elimination from palladium and proves that the nucelophile for this step stems from theimmediate coordination sphere of the palladium(IV) precursor. These results have important implicationsfor the general development of alkene 1,2-difunctionalization and for the individual processes ofaminopalladation and palladium-catalyzed C_alkyl-N bond formation.