Palladium-Catalyzed Cross-Coupling of Aziridinylmetal Species, Generated by Sulfinyl鈥揗agnesium Exchange, with Aryl Bromides: Reaction Optimization, Scope, and Kinetic Investigations

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• 作者：Matthew Hughes ; Tom Boultwood ; Gianfranco Zeppetelli ; James A. Bull
• 刊名：The Journal of Organic Chemistry
• 出版年：2013
• 出版时间：February 1, 2013
• 年：2013
• 卷：78
• 期：3
• 页码：844-854
• 全文大小：506K
• 年卷期：v.78,no.3(February 1, 2013)
• ISSN：1520-6904

文摘

A series of novel, highly substituted N-PMP aziridines have been accessed in high yields by palladium-catalyzed cross-coupling of intact aziridines. The cross-coupling employed aryl bromides and tertiary organometallic aziridines, generated from sulfinylaziridines by sulfinyl鈥搈agnesium exchange and transmetalation to the aziridinylzinc with zinc chloride. A wide range of electron-rich and electron-poor aryl bromides were utilized to afford the functionalized aziridine products as single diastereoisomers with retention of configuration at the reacting center. Assessment of the reaction kinetics showed zero-order in both the aziridine species and the aryl bromide. This indicated that the rate-determining step was reductive elimination from the palladium(II) species bearing both the aziridine and aryl groups to form the hindered C鈥揅 bond. The intermediate aziridinylzinc species underwent a progressive, background degradation that led to a plateau in yield and afforded reduced yields in substrates with ortho-substituted aryl groups, which are less reactive due to the additional steric demands.