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How To Perform Suzuki–Miyaura Reactions of Nitroarene or Nitrations of Bromoarene Using a Pd0 Phosphine Complex: Theoretical Insight and Prediction
Organometallics ( IF 2.5 ) Pub Date : 2018-07-06 , DOI: 10.1021/acs.organomet.8b00199
Rong-Lin Zhong 1 , Masahiro Nagaoka 2 , Yoshiaki Nakao 2 , Shigeyoshi Sakaki 1
Affiliation  

Pd0(BrettPhos) (1) was experimentally applied to Suzuki–Miyaura reactions of nitroarenes which occur through oxidative addition of nitroarene (ArNO2) to Pd0. On the other hand, Pd0(tBu-BrettPhos) (2) was experimentally applied to nitrations of bromoarenes which occur through reductive elimination of nitroarene. DFT calculations disclosed that oxidative addition of 4-nitroanisole to 1 was exergonic but that to 2 was endergonic, indicating that 1 is useful for oxidative addition of an Ar–NO2 bond but 2 is useful for reductive elimination of an Ar–NO2 bond. This difference in reactivity between 1 and 2 is explained in that bulky tBu groups on tBu-BrettPhos destabilize the PdII complex PdII(Ar)(NO2)(tBu-BrettPhos) due to large steric repulsion between Ar and tBu-BrettPhos but less bulky cyclohexyl groups on BrettPhos do not. It is theoretically predicted here that NMe2-substituted BrettPhos is better for Ar–NO2 bond cleavage than BrettPhos but xyl-BrettPhos is good for Ar–NO2 formation, as is tBu-BrettPhos, where NMe2 and 2,6-dimethylphenyl groups are introduced to BrettPhos instead of isopropyl and cyclohexyl groups, respectively.

中文翻译:

如何使用Pd 0膦配合物进行硝基芳烃的Suzuki-Miyaura反应或溴芳烃的硝化反应:理论见解和预测

Pd 0(BrettPhos)(1)已通过实验应用于硝基芳烃的Suzuki-Miyaura反应,该反应是通过将硝基芳烃(ArNO 2)氧化添加到Pd 0中而发生的。另一方面,将Pd 0t Bu-BrettPhos)(2)实验性地应用于溴代芳烃的硝化反应,该硝化反应是通过硝基消除亚硝基芳烃而实现的。DFT计算表明,将4-硝基茴香醚氧化加成为1是能动性的,而将2-硝基茴香醚氧化成是加成性的,这表明1可用于氧化加成Ar–NO 2键,而将2用于氧化加成。可用于还原性消除Ar–NO 2键。12之间反应性的差异是因为t Bu-BrettPhos上庞大的t Bu基团使Ar和t之间的空间排斥力大,使Pd II复合物Pd II(Ar)(NO 2)(t Bu-BrettPhos)不稳定。Bu-BrettPhos却没有,而BrettPhos上体积较小的环己基则没有。从理论上讲,NMe 2取代的BrettPhos对Ar–NO 2键的裂解比BrettPhos更好,但xyl-BrettPhos对Ar–NO 2的形成却有利。t Bu-BrettPhos,其中将NMe 2和2,6-二甲基苯基引入BrettPhos,分别取代异丙基和环己基。
更新日期:2018-07-08
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