Synthetic and Mechanistic Studies on Pd(0)-Catalyzed Diamination of Conjugated Dienes
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- 作者：Baoguo Zhao ; Haifeng Du ; Sunliang Cui ; Yian Shi
- 刊名：Journal of the American Chemical Society
- 出版年：2010
- 出版时间：March 17, 2010
- 年：2010
- 卷：132
- 期：10
- 页码：3523-3532
- 全文大小：492K
- 年卷期：v.132,no.10(March 17, 2010)
- ISSN：1520-5126
文摘
Various dienes and a triene can be regioselectively diaminated at the internal double bond with good yields and high diastereoselectivity using di-tert-butyldiaziridinone (5) as the nitrogen source and Pd(PPh3)4 (1−10 mol %) as the catalyst. Kinetic studies with 1H NMR spectroscopy show that the diamination is first-order in total Pd catalyst and inverse first-order in PPh3. For reactive dienes, such as 1-methoxybutadiene (6g) and alkyl 1,3-butadienes (6a, 6j), the diamination is first-order in di-tert-butyldiaziridinone (5) and zero-order in the olefin. For olefins with relatively low reactivity, such as (E)-1-phenylbutadiene (6b) and (3E,5E)-1,3,5-decatriene (6i), similar diamination rates were observed when 3.5 equiv of olefins were used. Pd(PPh3)2 is likely to be the active species for the insertion of Pd(0) into the N−N bond of di-tert-butyldiaziridinone (5) to form a four-membered Pd(II) complex (A), which can be detected by NMR spectroscopy. The olefin complex (B), formed from intermediate A via ligand exchange between the olefin substrate and the PPh3, undergoes migratory insertion and reductive elimination to give the diamination product and regenerate the Pd(0) catalyst.