The Role of the Fluoro–Hydrido–Phosphorane Intermediate in Catalytic Hydrosilylation of Acetophenone: Computational Study. Issue 2 (25th September 2018)

• Record Type: Journal Article
• Authors: Kostenko, Arseni; Dobrovetsky, Roman
• Other Names: Schreiner Peter R. guestEditor.
• Is Part Of: European journal of organic chemistry. Issue 2/3(2019)
• Page Start: 318
• Page End: 322
• Publication Date: 2018-09-25
• Subjects: Frustrated Lewis pairs -- Hydrosilylation -- Reaction mechanisms -- Electrophilic phosphonium cations -- Density functional calculations; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201800823
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract : The fluorophosphonium cation [(C6 F5 )3 PF] + (1 ) is used as a catalyst in many chemical transformations including the hydrosilylation of ketones. In these reactions the fluoro–hydrido–phosphorane (C6 F5 )3 PFH, which is formed upon a hydride abstraction by 1 from a hydrosilane, was proposed as the key intermediate. One of the most important features attributed to (C6 F5 )3 PFH in the catalytic hydrosilylation of ketones is its ability to transfer the hydride to an electrophile. However, (C6 F5 )3 FPH was not observed experimentally and its properties and in particular its hydride‐donating ability was not studied in detail. In this work the mode of formation of (C6 F5 )3 FPH, its properties and its interactions with substrates in the catalytic hydrosilylation of acetophenone were investigated by density functional theory (DFT), and possible routes of this catalytic reaction were studied. Calculations show that (C6 F5 )3 PFH can act both as a fluoride and hydride donor, and that these processes can exist in thermodynamic equilibrium. However, only the donation of the hydride results in intermediates that allow the catalytic cycle to proceed. Abstract : The formation of (C6 F5 )3 FPH and its interactions with substrates in the catalytic hydrosilylation of acetophenone were investigated by DFT. Calculations show that (C6 F5 )3 PFH can act both as a fluoride and a hydride donor, and that these processes can exist in thermodynamic equilibrium. However, only the donation of the hydride results in intermediates that allow the catalytic cycle to proceed.