Metal-free pincer ligand chemistry polycationic phosphonium Lewis acids

2017 ◽  
Vol 46 (12) ◽  
pp. 3921-3928 ◽  
Author(s):  
Kevin M. Szkop ◽  
Douglas W. Stephan
Keyword(s):  
Lewis Acid ◽  
Lewis Acids ◽  
Acid Catalysts ◽  
Phosphonium Salts ◽  
Lewis Acid Catalysts ◽  
Pincer Ligand ◽  
Metal Free ◽  
Methyl Pyridine

Oxidation with or without subsequent methylation of the pyridine of 2,6-bis(diphenylphosphine)methyl pyridine affords di- and tricationic phosphonium salts. These species are used as Lewis acid catalysts for the dimerization of 1,1-diphenylethylene, the hydrodefluorination of 1-fluoroadamantane, and the dehydrocoupling of phenol and silane.

Bidentate Lewis acid catalysts in asymmetric synthesis

2002 ◽  
Vol 74 (1) ◽  
pp. 123-128 ◽  
Author(s):  
Keiji Maruoka
Keyword(s):  
Asymmetric Synthesis ◽  
Organic Synthesis ◽  
Lewis Acid ◽  
Lewis Acids ◽  
Asymmetric Induction ◽  
Acid Catalysts ◽  
Lewis Acid Catalysts ◽  
High Chemical ◽  
Bidentate Lewis Acids

The chemistry of bidentate Lewis acids belongs to an unexplored field of science, and so far has been only poorly studied. This paper illustrates the design of several bidentate Al and Ti Lewis acids, and their successful application to selective organic synthesis, particularly to asymmetric synthesis. For example, a new, chiral bidentate Ti(IV) complex is successfully designed by adding commercially available Ti(OPri)4 and (S)-binaphthol sequentially to 2,2'-bis(tritylamino)-4,4'-dichlorobenzophenone in CH2Cl2, and can be utilized for simultaneous coordination to aldehyde carbonyls, thereby allowing the precise enantioface discrimination of such carbonyls for a new catalytic, practical enantioselective allylation of aldehydes with allyltributyltin. This chiral bidentate Ti(IV) catalyst exhibits uniformly high asymmetric induction as well as high chemical yields for various aldehydes. The present enantioselective allylation is highly chemoselective in the presence of other carbonyl moieties.

Tropylium salts as efficient organic Lewis acid catalysts for acetalization and transacetalization reactions in batch and flow

2017 ◽  
Vol 19 (17) ◽  
pp. 3993-3996 ◽  
Author(s):  
D. J. M. Lyons ◽  
R. D. Crocker ◽  
D. Enders ◽  
T. V. Nguyen
Keyword(s):  
Lewis Acid ◽  
Lewis Acids ◽  
Acid Catalysts ◽  
Lewis Acid Catalysts ◽  
Tropylium Salts

Tropylium salts were reported as organic-Lewis acids to efficiently catalyze acetalization reactions in batch and flow.

Air- and water-stable Lewis acids: synthesis and reactivity of P-trifluoromethyl electrophilic phosphonium cations

2018 ◽  
Vol 54 (6) ◽  
pp. 662-665 ◽  
Author(s):  
V. Fasano ◽  
J. H. W. LaFortune ◽  
J. M. Bayne ◽  
M. J. Ingleson ◽  
D. W. Stephan
Keyword(s):  
Lewis Acid ◽  
Lewis Acids ◽  
Acid Catalysts ◽  
Bronsted Acid ◽  
Lewis Acid Catalysts ◽  
Reaction Conditions ◽  
Brönsted Acid ◽  
And Function ◽  
Water Alcohol ◽  
Phosphonium Cations

Electrophilic phosphonium cations (EPCs) containing a –CF3 group are stable to air, water, alcohol and strong Brønsted acid and function as Lewis acid catalysts without requiring anhydrous reaction conditions.

Metal-Free Living Cationic Polymerization Using Diaryliodonium Salts as Organic Lewis Acid Catalysts

2020 ◽  
Vol 53 (11) ◽  
pp. 4185-4192
Author(s):  
Rui Haraguchi ◽  
Tsuyoshi Nishikawa ◽  
Arihiro Kanazawa ◽  
Sadahito Aoshima
Keyword(s):  
Lewis Acid ◽  
Cationic Polymerization ◽  
Acid Catalysts ◽  
Lewis Acid Catalysts ◽  
Free Living ◽  
Metal Free ◽  
Living Cationic Polymerization ◽  
Diaryliodonium Salts

Electrophilic phenoxy-substituted phosphonium cations

2016 ◽  
Vol 45 (45) ◽  
pp. 18156-18162 ◽  
Author(s):  
James H. W. LaFortune ◽  
Timothy C. Johnstone ◽  
Manuel Pérez ◽  
Daniel Winkelhaus ◽  
Vitali Podgorny ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Acid Catalysts ◽  
Phosphonium Salts ◽  
Lewis Acid Catalysts ◽  
Phosphonium Cations

A family of electrophilic phenoxy-substituted phosphonium salts [(RO)P(C6F5)3][B(C6F5)4] (R = C6H5, 4-FC6H4, 2,4-F2C6H3, C6F5) have been synthesized, used as Lewis acid catalysts and their air stability was evaluated.

scholarly journals Defunctionalisation catalysed by boron Lewis acids

2020 ◽  
Vol 11 (47) ◽  
pp. 12604-12615 ◽  
Author(s):  
Huaquan Fang ◽  
Martin Oestreich
Keyword(s):  
Lewis Acid ◽  
Lewis Acids ◽  
Acid Catalysts ◽  
Lewis Acid Catalysts

The combination of boron Lewis acid catalysts and hydride sources enables the cleavage of various carbon–heteroatom bonds.

Establishing the correlation between catalytic performance and N→Sb donor–acceptor interaction: systematic assessment of azastibocine halide derivatives as water tolerant Lewis acids

2019 ◽  
Vol 48 (23) ◽  
pp. 8478-8487 ◽  
Author(s):  
Jian Lei ◽  
Lingteng Peng ◽  
Renhua Qiu ◽  
Yongping Liu ◽  
Yi Chen ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Lewis Acids ◽  
Catalytic Performance ◽  
Acid Catalysts ◽  
Lewis Acid Catalysts ◽  
Acceptor Interaction ◽  
Systematic Assessment ◽  
Donor Acceptor ◽  
Halide Complexes

A series of organoantimony(iii) halide complexes with a tetrahydrodibenzo[c,f][1,5]azastibocine framework were synthesized and employed as water tolerant Lewis acid catalysts.

scholarly journals Boron-Based Lewis Acid Catalysis: Challenges and Perspectives

Catalysts ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 5
Author(s):  
Valeria Nori ◽  
Fabio Pesciaioli ◽  
Arianna Sinibaldi ◽  
Giuliana Giorgianni ◽  
Armando Carlone
Keyword(s):  
Organic Synthesis ◽  
Lewis Acid ◽  
Gold Standard ◽  
Lewis Acids ◽  
Acid Catalysis ◽  
Acid Catalysts ◽  
Chemical Transformations ◽  
Lewis Acid Catalysis ◽  
Lewis Acid Catalysts ◽  
Better Than

In the last two decades, boron-based catalysis has been gaining increasing traction in the field of organic synthesis. The use of halogenated triarylboranes as main group Lewis acid catalysts is an attractive strategy. It has been applied in a growing number of transformations over the years, where they may perform comparably or even better than the gold standard catalysts. This review discusses methods of borane synthesis and cutting-edge boron-based Lewis acid catalysis, focusing especially on tris(pentafluorophenyl)-borane [B(C6F5)3], and other halogenated triarylboranes, highlighting how boron Lewis acids employed as catalysts can unlock a plethora of unprecedented chemical transformations or improve the efficiency of existing reactions.

Synthesis and Applications of Chiral Bicyclic Bisborane Catalysts

Synthesis ◽  
2021 ◽  
Author(s):  
Zhao-Ying Yang ◽  
Ming Zhang ◽  
Xiao-Chen Wang
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Asymmetric Hydrogenation ◽  
Acid Catalysts ◽  
Frustrated Lewis Pairs ◽  
Lewis Acid Catalysts ◽  
Lewis Bases ◽  
Metal Free ◽  
Hydrogenation Reactions ◽  
Acid Catalyzed

The development of chiral borane Lewis acid catalysts opened the door for transition-metal-free catalyzed asymmetric organic reactions. Herein, we have summarized our work on the preparation of two classes of novel chiral bicyclic bisborane Lewis acid catalysts derived from C2-symmetric [3.3.0] dienes and [4.4] dienes, respectively. These catalysts not only form frustrated Lewis pairs with Lewis bases to catalyze asymmetric hydrogenation reactions but also activate Lewis basic functional groups in traditional Lewis acid catalyzed asymmetric reactions.

scholarly journals Efficient Synthesis Of Alkyl And Aryl 2,3-Unsaturated Glycopyranosides via Ferrier Rearrangement

2014 ◽  
Vol 7 (2) ◽  
Author(s):  
Dayang Halimatulzahrah Abang Kamal ◽  
Zainab Ngaini
Keyword(s):  
Aromatic Ring ◽  
Lewis Acid ◽  
Lewis Acids ◽  
Aliphatic Alcohol ◽  
Reaction Times ◽  
Acid Catalysts ◽  
Efficient Synthesis ◽  
Lewis Acid Catalysts ◽  
Ferrier Rearrangement

The reactions of 3,4,6-tri-O-acetyl-D-glucal with phenolic and aliphatic alcohol in various Lewis acid catalysts (namely La(NO3)3.6H2O, InCl3, ZnCl2 and BF3•OEt2) have furnished the corresponding alkyl and aryl 2,3-unsaturated glycopyranosides via Ferrier rearrangement. BF3•OEt2 showed the best Lewis acids catalysts with excellent yields and minimum reaction times. The reactions performed in CH3CN gave better yields and shorter reaction times compared to CH2Cl2. The electron withdrawing properties of aromatic ring resulting lower yields of aryl 2,3-unsaturated glycopyranosides compared to alkyl 2,3-unsaturated glycopyranosides under this condition. This study is significant in the preparation of O-glycosides via Ferrier rearrangement.

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