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Computational study of selectivity in the [PtIICl4]2−-catalysed arylation of arenes by diaryliodonium reagents: arene activation at PtIV centres
Dalton Transactions ( IF 3.5 ) Pub Date : 2017-10-23 00:00:00 , DOI: 10.1039/c7dt03602g
Allan J. Canty 1, 2, 3, 4 , Alireza Ariafard 1, 2, 3, 4, 5
Affiliation  

The mechanism for the [PtIICl4]2−-catalysed reaction of Ph2IIII(TFA) (TFA = trifluoroacetate) with naphthalene (NapH) to give β-phenylation over α-phenylation of naphthalene has been examined by computational methods. In support of the mechanism proposed by Sanford based on experimental evidence, reaction commences by oxidative phenyl transfer from [Ph2I]+ to [PtIICl4]2−, giving trans-[PhPtIVCl4(TFA)]2−. Transformation to cis-[PhPtIVCl3(TFA)] leads to reaction with NapH at the β-position in an inner-sphere Concerted Metalation Deprotonation (CMD) manner to give cis-[Ph(Nap)PtIVCl3] and trifluoroacetic acid. Reductive elimination yields β-PhNap, and coordination of chloride regenerates [PtIICl4]2− for subsequent catalytic cycles. The selectivity for β-phenylation over α-phenylation is attributable to steric factors in the CMD PtIV transition state containing a higher coordination number than that occurring for related reactions in PdII catalysis that gives α-phenylation.

中文翻译:

芳基碘鎓试剂在[Pt II Cl 4 ] 2-催化芳烃芳基化中选择性的计算研究:Pt IV中心的芳烃活化

通过计算方法研究了[Pt II Cl 4 ] 2-催化Ph 2 I III(TFA)(TFA =三氟乙酸盐)与萘(NapH)生成β-苯基化反应而不是萘的α-苯基化反应的机理。。为了支持桑福德基于实验证据提出的机理,反应通过从[Ph 2 I] +到[Pt II Cl 4 ] 2-的氧化苯基转移而开始,得到反式-[PhPt IV Cl 4(TFA)] 2-。转化为顺式-[PhPt IVCl 3(TFA)] -以内球协同金属化去质子化(CMD)的方式与NapH处的NapH反应,生成顺式-[Ph(Nap)Pt IV Cl 3 ] -和三氟乙酸。还原消除产生β-PhNap,氯化物的配位体在随后的催化循环中再生[Pt II Cl 4 ] 2-。β-苯基化相对于α-苯基化的选择性归因于CMD Pt IV过渡态中的空间因素,该立体因素具有比在产生α-苯基化的Pd II催化中相关反应更高的配位数。
更新日期:2017-11-15
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