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>

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>

scholarly journals Lewis Acid Catalyzed Carbonyl–Olefin Metathesis

Synlett ◽  
2017 ◽  
Vol 28 (13) ◽  
pp. 1501-1509 ◽  
Author(s):  
Corinna Schindler ◽  
Jacob Ludwig
Keyword(s):  
Lewis Acid ◽  
Olefin Metathesis ◽  
Chemical Biology ◽  
Materials Science ◽  
Bond Formation ◽  
Synthetic Chemistry ◽  
Carbon Bond ◽  
Carbon Carbon Bond ◽  
Metathesis Reactions ◽  
Acid Catalyzed

Olefin–olefin metathesis has led to important advances in diverse fields of research, including synthetic chemistry, materials science, and chemical biology. The corresponding carbonyl–olefin metathesis also enables direct carbon–carbon bond formation from readily available precursors, however, currently available synthetic procedures are significantly less advanced. This Synpacts article provides an overview of recent achievements in the field of Lewis acid mediated and Lewis acid catalyzed carbonyl–olefin metathesis reactions.1 Lewis Acid Mediated Carbonyl–Olefin Metathesis2 Lewis Acid Catalyzed Carbonyl–Olefin Metathesis

scholarly journals Models for Understanding Divergent Reactivity in Lewis Acid-Catalyzed Transformations of Carbonyls and Olefins

2019 ◽  
Author(s):  
Marc R. Becker ◽  
Jolene P. Reid ◽  
Katie Rykaczewski ◽  
Corinna Schindler
Keyword(s):  
Lewis Acid ◽  
Olefin Metathesis ◽  
Lewis Acids ◽  
Potential Energy Surfaces ◽  
High Selectivity ◽  
Linear Regression Models ◽  
Lewis Acid Catalysts ◽  
Carbon Carbon Bond ◽  
Acid Catalyzed ◽  
Energy Surfaces

<div>Carbonyl-ene, Prins and carbonyl-olefin metathesis reactions represent powerful strategies for carbon-carbon bond formation relying on Lewis acid catalysts. Although common Lewis acids are able to provide efficient activation, the reactions often proceed with low regio-, or chemoselectivity while high selectivity frequently requires the use of well-designed metal-ligand complexes. Here we demonstrate that simple Lewis acids including Me<sub>2</sub>AlCl, FeCl<sub>3</sub>, and SnCl<sub>4</sub> can show remarkable selectivity in dif-ferentiating between distinct transformations of carbonyl and olefin functional groups resulting in either carbonyl-ene or carbonyl-olefin metathesis products. Specifically, we report the development of predictive multivariate linear regression models that rely on kinetic and thermodynamic information obtained in DFT calculations to gain important insights into the complex potential energy surfaces (PES) of these competing reaction paths. The presented results further our understanding of Lewis acid reactivity and suggest that even simple Lewis acids have the potential to function as highly selective catalysts.</div>

scholarly journals Models for Understanding Divergent Reactivity in Lewis Acid-Catalyzed Transformations of Carbonyls and Olefins

2019 ◽  
Author(s):  
Marc R. Becker ◽  
Jolene P. Reid ◽  
Katie Rykaczewski ◽  
Corinna Schindler
Keyword(s):  
Lewis Acid ◽  
Olefin Metathesis ◽  
Lewis Acids ◽  
Potential Energy Surfaces ◽  
High Selectivity ◽  
Linear Regression Models ◽  
Lewis Acid Catalysts ◽  
Carbon Carbon Bond ◽  
Acid Catalyzed ◽  
Energy Surfaces

<div>Carbonyl-ene, Prins and carbonyl-olefin metathesis reactions represent powerful strategies for carbon-carbon bond formation relying on Lewis acid catalysts. Although common Lewis acids are able to provide efficient activation, the reactions often proceed with low regio-, or chemoselectivity while high selectivity frequently requires the use of well-designed metal-ligand complexes. Here we demonstrate that simple Lewis acids including Me<sub>2</sub>AlCl, FeCl<sub>3</sub>, and SnCl<sub>4</sub> can show remarkable selectivity in dif-ferentiating between distinct transformations of carbonyl and olefin functional groups resulting in either carbonyl-ene or carbonyl-olefin metathesis products. Specifically, we report the development of predictive multivariate linear regression models that rely on kinetic and thermodynamic information obtained in DFT calculations to gain important insights into the complex potential energy surfaces (PES) of these competing reaction paths. The presented results further our understanding of Lewis acid reactivity and suggest that even simple Lewis acids have the potential to function as highly selective catalysts.</div>

scholarly journals Catalytic, Transannular Carbonyl-Olefin Metathesis Reactions

2019 ◽  
Author(s):  
Paul Riehl ◽  
Daniel Nasrallah ◽  
Corinna Schindler
Keyword(s):  
Lewis Acid ◽  
Olefin Metathesis ◽  
Ring Opening ◽  
Acid Catalyst ◽  
Catalyst Design ◽  
Lewis Acid Catalysts ◽  
Complex Molecules ◽  
New Class ◽  
Metathesis Reactions ◽  
Lewis Acid Catalyst

A new class of Lewis acid-catalyzed carbonyl-olefin metathesis reactions is described that complements existing protocols for related ring-closing, ring-opening, and intermolecular transformations. These transannular carbonyl-olefin metathesis reactions rely on FeCl<sub>3</sub> as an inexpensive Lewis acid catalyst and are mechanistically distinct from previously developed protocols for ring closing, ring-opening and intermolecular metathesis. Specifically, carbonyl-ene and carbonyl-olefin metathesis reaction paths are competing to ultimately favor metathesis as the thermodynamic product. Importantly, we show that distinct Lewis acid catalysts are able to differentiate between these pathways to enable the selective formation of transannular carbonyl-ene or carbonyl-olefin metathesis products thus providing a valuable approach to the molecular editing of naturally occurring complex molecules. Additionally, these results are expected to enable further advances in catalyst design for carbonyl-olefin metathesis to ultimately develop efficient and high-yielding catalytic carbonyl olefination reactions.

scholarly journals Catalytic, Transannular Carbonyl-Olefin Metathesis Reactions

2019 ◽  
Author(s):  
Paul Riehl ◽  
Daniel Nasrallah ◽  
Corinna Schindler
Keyword(s):  
Lewis Acid ◽  
Olefin Metathesis ◽  
Ring Opening ◽  
Acid Catalyst ◽  
Catalyst Design ◽  
Lewis Acid Catalysts ◽  
Complex Molecules ◽  
New Class ◽  
Metathesis Reactions ◽  
Lewis Acid Catalyst

A new class of Lewis acid-catalyzed carbonyl-olefin metathesis reactions is described that complements existing protocols for related ring-closing, ring-opening, and intermolecular transformations. These transannular carbonyl-olefin metathesis reactions rely on FeCl<sub>3</sub> as an inexpensive Lewis acid catalyst and are mechanistically distinct from previously developed protocols for ring closing, ring-opening and intermolecular metathesis. Specifically, carbonyl-ene and carbonyl-olefin metathesis reaction paths are competing to ultimately favor metathesis as the thermodynamic product. Importantly, we show that distinct Lewis acid catalysts are able to differentiate between these pathways to enable the selective formation of transannular carbonyl-ene or carbonyl-olefin metathesis products thus providing a valuable approach to the molecular editing of naturally occurring complex molecules. Additionally, these results are expected to enable further advances in catalyst design for carbonyl-olefin metathesis to ultimately develop efficient and high-yielding catalytic carbonyl olefination reactions.

scholarly journals Catalytic, Transannular Carbonyl-Olefin Metathesis Reactions

2019 ◽  
Author(s):  
Paul Riehl ◽  
Daniel Nasrallah ◽  
Corinna Schindler
Keyword(s):  
Lewis Acid ◽  
Olefin Metathesis ◽  
Ring Opening ◽  
Acid Catalyst ◽  
Catalyst Design ◽  
Lewis Acid Catalysts ◽  
Complex Molecules ◽  
New Class ◽  
Metathesis Reactions ◽  
Lewis Acid Catalyst

A new class of Lewis acid-catalyzed carbonyl-olefin metathesis reactions is described that complements existing protocols for related ring-closing, ring-opening, and intermolecular transformations. These transannular carbonyl-olefin metathesis reactions rely on FeCl<sub>3</sub> as an inexpensive Lewis acid catalyst and are mechanistically distinct from previously developed protocols for ring closing, ring-opening and intermolecular metathesis. Specifically, carbonyl-ene and carbonyl-olefin metathesis reaction paths are competing to ultimately favor metathesis as the thermodynamic product. Importantly, we show that distinct Lewis acid catalysts are able to differentiate between these pathways to enable the selective formation of transannular carbonyl-ene or carbonyl-olefin metathesis products thus providing a valuable approach to the molecular editing of naturally occurring complex molecules. Additionally, these results are expected to enable further advances in catalyst design for carbonyl-olefin metathesis to ultimately develop efficient and high-yielding catalytic carbonyl olefination reactions.

scholarly journals Catalytic, Transannular Carbonyl-Olefin Metathesis Reactions

2019 ◽  
Author(s):  
Paul Riehl ◽  
Daniel Nasrallah ◽  
Corinna Schindler
Keyword(s):  
Lewis Acid ◽  
Olefin Metathesis ◽  
Ring Opening ◽  
Acid Catalyst ◽  
Catalyst Design ◽  
Lewis Acid Catalysts ◽  
Complex Molecules ◽  
New Class ◽  
Metathesis Reactions ◽  
Lewis Acid Catalyst

A new class of Lewis acid-catalyzed carbonyl-olefin metathesis reactions is described that complements existing protocols for related ring-closing, ring-opening, and intermolecular transformations. These transannular carbonyl-olefin metathesis reactions rely on FeCl<sub>3</sub> as an inexpensive Lewis acid catalyst and are mechanistically distinct from previously developed protocols for ring closing, ring-opening and intermolecular metathesis. Specifically, carbonyl-ene and carbonyl-olefin metathesis reaction paths are competing to ultimately favor metathesis as the thermodynamic product. Importantly, we show that distinct Lewis acid catalysts are able to differentiate between these pathways to enable the selective formation of transannular carbonyl-ene or carbonyl-olefin metathesis products thus providing a valuable approach to the molecular editing of naturally occurring complex molecules. Additionally, these results are expected to enable further advances in catalyst design for carbonyl-olefin metathesis to ultimately develop efficient and high-yielding catalytic carbonyl olefination reactions.

Lewis acid-catalyzed tandem cyclization of in situ generated o-quinone methides and arylsulfonyl hydrazides for a one-pot entry to 3-sulfonylbenzofurans

2019 ◽  
Vol 6 (24) ◽  
pp. 3929-3933 ◽  
Author(s):  
Fan-Xiao Meng ◽  
Ruo-Nan Wang ◽  
Hong-Li Huang ◽  
Shu-Wen Gong ◽  
Qian-Li Li ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Quinone Methides ◽  
One Pot ◽  
Acid Catalyzed ◽  
Tandem Cyclization ◽  
First Time

Lewis acid-mediated one-pot tandem cyclization of o-QMs with arylsulfonyl hydrazides was described for the first time and the corresponding 3-sulfonylbenzofuran products were obtained in moderate to good yields.

scholarly journals A three-component, Zn(OTf)2-mediated entry into trisubstituted 2-aminoimidazoles

2019 ◽  
Vol 15 ◽  
pp. 1061-1064 ◽  
Author(s):  
Alexei Lukin ◽  
Anna Bakholdina ◽  
Anna Kryukova ◽  
Alexander Sapegin ◽  
Mikhail Krasavin
Keyword(s):  
Lewis Acid ◽  
Primary Amine ◽  
Three Component Reaction ◽  
Acid Catalyzed ◽  
In Situ Generation

A three-component reaction involving in situ generation of propargylureas and subsequent Zn(OTf)2-mediated cyclocondensation with a primary amine yielded trisubstituted 2-aminoimidazoles. These findings are in contrast to the previously reported base-promoted unimolecular cyclization of propargylureas (leading to 2-imidazolones) and extend the range of Lewis acid-catalyzed azole syntheses based on N-carbonyl propargylamines.

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