Lewis Acid-Driven Accelerated Living Polymerization of Lactones Initiated with Aluminum Porphyrins. Chemoselective Activation of Ester Groups by Lewis Acid

1997 ◽  
Vol 30 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Masanori Isoda ◽  
Hiroshi Sugimoto ◽  
Takuzo Aida ◽  
Shohei Inoue
Keyword(s):  
Lewis Acid ◽  
Living Polymerization

Living polymerization of naturally renewable butyrolactone-based vinylidenes mediated by a frustrated Lewis pair

2021 ◽  
Vol 12 (38) ◽  
pp. 5548-5555
Author(s):  
Yun Bai ◽  
Huaiyu Wang ◽  
Jianghua He ◽  
Yuetao Zhang
Keyword(s):  
Lewis Acid ◽  
Living Polymerization ◽  
Controlled Polymerization ◽  
Frustrated Lewis Pair

The frustrated Lewis pair composed of an organophosphorus(iii) superbase and a bulky organoaluminum Lewis acid promoted the living/controlled polymerization of naturally renewable butyrolactone-based vinylidenes.

Living polymerization of acrylamides catalysed by N-heterocyclic olefin-based Lewis pairs

2019 ◽  
Vol 10 (26) ◽  
pp. 3597-3603 ◽  
Author(s):  
Huaiyu Wang ◽  
Qianyi Wang ◽  
Jianghua He ◽  
Yuetao Zhang
Keyword(s):  
Lewis Acid ◽  
Living Polymerization ◽  
Lewis Base ◽  
Controlled Polymerization ◽  
Lewis Pairs

Living/controlled polymerization of acrylamides achieved by a Lewis pair composed of an N-heterocyclic olefin as a Lewis base and triphenylaluminum as a Lewis acid.

Cobalt/Lewis Acid Catalysis for Hydrocarbofunctionalization of Alkynes via Cooperative C–H Activation

2020 ◽  
Author(s):  
Chang-Sheng Wang ◽  
Sabrina Monaco ◽  
Anh Ngoc Thai ◽  
Md. Shafiqur Rahman ◽  
Chen Wang ◽  
...  
Keyword(s):  
Catalytic System ◽  
Lewis Acid ◽  
Hydrogen Transfer ◽  
Acid Catalysis ◽  
Rate Limiting Step ◽  
Site Selectivity ◽  
Set Up ◽  
Site Selective ◽  
First Time ◽  
Rate Limiting

A catalytic system comprised of a cobalt-diphosphine complex and a Lewis acid (LA) such as AlMe3 has been found to promote hydrocarbofunctionalization reactions of alkynes with Lewis basic and electron-deficient substrates such as formamides, pyridones, pyridines, and azole derivatives through site-selective C-H activation. Compared with known Ni/LA catalytic system for analogous transformations, the present catalytic system not only feature convenient set up using inexpensive and bench-stable precatalyst and ligand such as Co(acac)3 and 1,3-bis(diphenylphosphino)propane (dppp), but also display distinct site-selectivity toward C-H activation of pyridone and pyridine derivatives. In particular, a completely C4-selective alkenylation of pyridine has been achieved for the first time. Mechanistic stidies including DFT calculations on the Co/Al-catalyzed addition of formamide to alkyne have suggested that the reaction involves cleavage of the carbamoyl C-H bond as the rate-limiting step, which proceeds through a ligand-to-ligand hydrogen transfer (LLHT) mechanism leading to an alkyl(carbamoyl)cobalt intermediate.

Catalytic Carbonyl-Olefin Metathesis of Aliphatic Ketones: Iron(III) HomoDimers as Lewis Acidic Superelectrophiles

2018 ◽  
Author(s):  
Haley Albright ◽  
Paul S. Riehl ◽  
Christopher C. McAtee ◽  
Jolene P. Reid ◽  
Jacob R. Ludwig ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Olefin Metathesis ◽  
Acid Activation ◽  
Lewis Acid Catalysts ◽  
Distinct Mode ◽  
Aliphatic Ketones ◽  
Carbon Carbon Bond ◽  
Metathesis Reactions ◽  
Acid Catalyzed

<div>Catalytic carbonyl-olefin metathesis reactions have recently been developed as a powerful tool for carbon-carbon bond</div><div>formation. However, currently available synthetic protocols rely exclusively on aryl ketone substrates while the corresponding aliphatic analogs remain elusive. We herein report the development of Lewis acid-catalyzed carbonyl-olefin ring-closing metathesis reactions for aliphatic ketones. Mechanistic investigations are consistent with a distinct mode of activation relying on the in situ formation of a homobimetallic singly-bridged iron(III)-dimer as the active catalytic species. These “superelectrophiles” function as more powerful Lewis acid catalysts that form upon association of individual iron(III)-monomers. While this mode of Lewis acid activation has previously been postulated to exist, it has not yet been applied in a catalytic setting. The insights presented are expected to enable further advancement in Lewis acid catalysis by building upon the activation principle of “superelectrophiles” and broaden the current scope of catalytic carbonyl-olefin metathesis reactions.</div>

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