Structure–Reactivity Relationships in Negishi Cross‐Coupling Reactions |
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| Authors: | Zhi‐Bing Dong Dr Georg Manolikakes Dr Lei Shi Dr Paul Knochel Prof Dr Herbert Mayr Prof Dr |
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| Institution: | 1. School of Chemistry and Chemical Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu (China);2. Department Chemie und Biochemie, Ludwig‐Maximilians‐Universit?t München, Butenandtstrasse 5–13 (Haus F), 81377 München (Germany), Fax: (+49)?89‐2180‐77717 |
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| Abstract: | Competition experiments have been performed to determine the relative reactivities of substituted bromobenzenes and of different arylzinc reagents in the Pd(PPh3)4]‐catalyzed Negishi cross‐coupling reaction in THF at 25 °C. The cross‐coupling reactions are accelerated by electron acceptors in the bromobenzenes, the effect of which increases in the order ortho <meta <para. On the other hand, electron acceptors in the arylzinc halides diminish the reaction rates. Hammett correlations show that substituent variations in the bromobenzenes (ρ=+2.5) have a larger effect than substituent variations in the arylzinc halides (ρ=?0.98). |
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| Keywords: | C?C bond formation Hammett equation kinetics reaction mechanisms substituent effects |
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