Synthesis and Lewis acidity of fluorophosphonium cations

2015 ◽  
Vol 44 (27) ◽  
pp. 12256-12264 ◽  
Author(s):  
Christopher B. Caputo ◽  
Daniel Winkelhaus ◽  
Roman Dobrovetsky ◽  
Lindsay J. Hounjet ◽  
Douglas W. Stephan
Keyword(s):  
Lewis Acidity ◽  
Frustrated Lewis Pairs ◽  
Lewis Pairs

A series of fluorophosphonium salts, [R3PF][X] (R = alkyl or aryl; X = FB(C6F5)3, [B(C6F5)4]), have been prepared by reactions of phosphine/borane frustrated Lewis pairs (FLPs) with XeF2 or difluorophosphoranes with [Et3Si][B(C6F5)4].

Design considerations for chiral frustrated Lewis pairs: B/N FLPs derived from 3,5-bicyclic aryl piperidines

2019 ◽  
Vol 48 (1) ◽  
pp. 133-141 ◽  
Author(s):  
Jolie Lam ◽  
Susanna Sampaolesi ◽  
James H. W. LaFortune ◽  
Jotham W. Coe ◽  
Douglas W. Stephan
Keyword(s):  
Computational Methods ◽  
Lewis Acidity ◽  
Frustrated Lewis Pairs ◽  
Design Considerations ◽  
Acidity And Basicity ◽  
Lewis Pairs

3,5-Bicyclic aryl piperidines are derivatized to generate chiral B/N FLPs. The Lewis acidities were assessed by experimental and computational methods. The activity in HD scrambling and hydrogenation was also assessed. These data demonstrate that a threshold of combined Lewis acidity and basicity is essential to activate H2.

Azaborines: synthesis and use in the generation of stabilized boron-substituted carbocations

2018 ◽  
Vol 47 (6) ◽  
pp. 1791-1795 ◽  
Author(s):  
J. J. Clarke ◽  
P. Eisenberger ◽  
S. S. Piotrkowski ◽  
C. M. Crudden
Keyword(s):  
Lewis Acids ◽  
Ring Expansion ◽  
Lewis Acidity ◽  
Frustrated Lewis Pairs ◽  
Carbene Insertion ◽  
Hydride Abstraction ◽  
Ring Expansion Reaction ◽  
Lewis Pairs

A formal N-heterocyclic carbene insertion into the B–H bond of 9-BBN followed by a ring expansion reaction is reported. NHC-9-BBN adducts were reacted in one or two steps to give the corresponding di- or triazaborines. Hydride abstraction of selected species with [Ph3C]+ is facile, giving rise to 6π-aromatic cations with Lewis acidity comparable to Lewis acids commonly employed in frustrated Lewis pairs.

Tuning Lewis acidity using the reactivity of “frustrated Lewis pairs”: facile formation of phosphine-boranes and cationic phosphonium-boranes

2007 ◽  
pp. 3407 ◽  
Author(s):  
Gregory C. Welch ◽  
Lourdes Cabrera ◽  
Preston A. Chase ◽  
Emily Hollink ◽  
Jason D. Masuda ◽  
...  
Keyword(s):  
Lewis Acidity ◽  
Frustrated Lewis Pairs ◽  
Lewis Pairs

scholarly journals Halogenated triphenylgallium and -indium in frustrated Lewis pair activations and hydrogenation catalysis

2017 ◽  
Vol 375 (2101) ◽  
pp. 20170014 ◽  
Author(s):  
Maotong Xu ◽  
Josephine Possart ◽  
Alexander E. Waked ◽  
Julie Roy ◽  
Werner Uhl ◽  
...  
Keyword(s):  
Lewis Acids ◽  
Lewis Acidity ◽  
Frustrated Lewis Pairs ◽  
Frustrated Lewis Pair ◽  
Hydrogenation Catalysis ◽  
Lewis Pairs

The Lewis acids Ga(C 6 F 5 ) 3 , In(C 6 F 5 ) 3 and Ga(C 6 Cl 5 ) 3 are prepared and their Lewis acidity has been probed experimentally and computationally. The species Ga(C 6 F 5 ) 3 and In(C 6 F 5 ) 3 in conjunction with phosphine donors are shown to heterolytically split H 2 and catalyse the hydrogenation of an imine. In addition, frustrated Lewis pairs (FLPs) derived from Ga(C 6 F 5 ) 3 and In(C 6 F 5 ) 3 and phosphines react with diphenyldisulfide to phosphoniumgallates or indates of the form [ t Bu 3 PSPh][PhSE(C 6 F 5 ) 3 ] and [ t Bu 3 PSPh][(μ-SPh)(E(C 6 F 5 ) 3 ) 2 ] (E = Ga, In). The potential of the FLPs based on Ga(C 6 F 5 ) 3 , In(C 6 F 5 ) 3 and Ga(C 6 Cl 5 ) 3 and phosphines is also shown in reactions with phenylacetylene to give pure or mixtures of the products [ t Bu 3 PH][PhCCE(C 6 X 5 ) 3 ] and R 3 P(Ph)C=C(H)E(C 6 X 5 ) 3 . A number of these species are crystallographically characterized. The implications for the use of these species in FLP chemistry are considered. This article is part of the themed issue ‘Frustrated Lewis pair chemistry’.

Theoretical Evaluation of the Efficiency of Novel Frustrated Lewis Pairs in the cis-Hydrogenation Reaction of Dimethylacetylene

2017 ◽  
Vol 42 (4) ◽  
pp. 372-383 ◽  
Author(s):  
Nazanin Noroozi-Shad ◽  
Mostafa Gholizadeh ◽  
Mohammad Izadyar ◽  
Hossein Eshghi
Keyword(s):  
Lewis Acid ◽  
Hydrogenation Reaction ◽  
Lewis Acidity ◽  
Small Molecule Activation ◽  
Frustrated Lewis Pairs ◽  
Theoretical Evaluation ◽  
Wide Range ◽  
Acid And Base ◽  
Lewis Acid And Base ◽  
Lewis Pairs

Frustrated Lewis pairs (FLPs) are the combination of Lewis acid and base motifs where steric hindrance prevents strong adduct formation. Accordingly, the ability of FLPs in small molecule activation and their capability in hydrogen cleavage led to their use in the hydrogenation of a wide range of unsaturated substrates. Here, we investigated theoretically the ability of three intramolecular phosphorus/boron FLPs as bifunctional catalysts in the metal-free hydrogenation of dimethylacetylene to cis-alkene. The mechanism of this hydrogenation reaction, based on the boron acceptor [including –OR substituents (B(OR)2), where R is an aliphatic or aromatic branch] and phosphorus donor, has been explored. Based on the results obtained, it was confirmed that the H2 splitting reaction and the formation of the phosphonium–borohydride motifs for these FLPs are endothermic. It has been shown that these FLPs have a moderate ability in H–H bond splitting. Also, the capability of the boron atom in FLPs on the hydrogenation reaction was investigated. The reduction steps of the mechanism showed an exothermic nature. This result revealed that the presence of the boron as a Lewis acid, with a very limited Lewis acidity, improves the catalytic hydrogenation reaction significantly. Finally, it was confirmed that the proposed FLPs in the cis-hydrogenation of alkynes will be effective.

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