Hydrosilylation of ketones, imines and nitriles catalysed by electrophilic phosphonium cations: Functional group selectivity and mechanistic considerations

Manuel Pérez, Zheng Wang Qu, Christopher B. Caputo, Vitali Podgorny, Lindsay J. Hounjet, Andreas Hansen, Roman Dobrovetsky, Stefan Grimme, Douglas W. Stephan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The electrophilic phosphonium salt, [(C6F5)3PF][B(C6F5)4], catalyses the efficient hydrosilylation of ketones, imines and nitriles at room temperature. In the presence of this catalyst, adding one equivalent of hydrosilane to a nitrile yields a silylimine product, whereas adding a second equivalent produces the corresponding disilylamine. [(C6F5)3PCl][B(C6F5)4] and [(C6F5)3PBr][B(C6F5)4] are also synthesised and tested as catalysts. Competition experiments demonstrate that the reaction exhibits selectivity for the following functional groups in order of preference: ketone>nitrile>imine>olefin. Computational studies reveal the reaction mechanism to involve initial activation of the Si-H bond by its interaction with the phosphonium centre. The activated complex then acts cooperatively on the unsaturated substrate. Proceed with cation: The electrophilic phosphonium salt, [(C6F5)3PF][B(C6F5)4], catalyses the efficient hydrosilylation of ketones, imines and nitriles at room temperature. In the presence of this catalyst, adding one equivalent of hydrosilane to a nitrile yields a silylimine product, whereas adding a second equivalent produces the corresponding disilylamine.

Original languageEnglish
Pages (from-to)6491-6500
Number of pages10
JournalChemistry - A European Journal
Volume21
Issue number17
DOIs
StatePublished - 20 Apr 2015
Externally publishedYes

Keywords

  • homogeneous catalysis
  • hydrosilylation
  • phosphonium
  • reaction mechanisms
  • selectivity

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