Ground-State Electron Transfer as an Initiation Mechanism for Biocatalytic C–C Bond Forming Reactions

2021 ◽  
Author(s):  
Haigen Fu ◽  
Heather Lam ◽  
Megan A. Emmanuel ◽  
Ji Hye Kim ◽  
Braddock A. Sandoval ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Ground State ◽  
Initiation Mechanism ◽  
Bond Forming ◽  
State Electron ◽  
Bond Forming Reactions ◽  
Ground State Electron

scholarly journals Ground-State Electron Transfer as an Initiation Mechanism for Asymmetric Hydroalkylations in Radical Biocatalysis

2021 ◽  
Author(s):  
Haigen Fu ◽  
Heather Lam ◽  
Megan Emmanuel ◽  
Ji Hye Kim ◽  
Braddock Sandoval ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Ground State ◽  
Saturation Mutagenesis ◽  
Wild Type ◽  
Initiation Mechanism ◽  
Radical Initiation ◽  
Enzyme Active Site ◽  
Bond Forming ◽  
State Electron ◽  
Ground State Electron

<p>Stereoselective bond-forming reactions are essential tools in modern organic synthesis. However, catalytic strategies for controlling the stereochemical outcome of radical-mediated C–C bond formation remain underdeveloped.<b> </b>Here, we report an ‘ene’-reductase catalyzed asymmetric hydroalkylation of olefins using α-bromoketones as radical precursors. In these reactions, radical initiation occurs <i>via</i> ground-state electron transfer from the flavin cofactor located within the enzyme active site, representing a mechanistic departure from previous photoenzymatic hydroalkylations. Four rounds of site saturation mutagenesis based on wild-type nicotinamide-dependent cyclohexanone reductase (NCR) were deployed to access a variant capable of catalyzing a cyclization to furnish β-chiral cyclopentanones with high levels of enantioselectivity. Additionally, the wild-type NCR was identified that could catalyze the intermolecular coupling with precise stereochemical control over the radical termination step. This report demonstrates this enzyme family’s catalytic versatility and highlights the opportunity for protein engineering to address reactivity and selectivity challenges in radical biocatalysis. </p>

scholarly journals Ground-State Electron Transfer as an Initiation Mechanism for Asymmetric Hydroalkylations in Radical Biocatalysis

2021 ◽  
Author(s):  
Haigen Fu ◽  
Heather Lam ◽  
Megan Emmanuel ◽  
Ji Hye Kim ◽  
Braddock Sandoval ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Ground State ◽  
Saturation Mutagenesis ◽  
Wild Type ◽  
Initiation Mechanism ◽  
Radical Initiation ◽  
Enzyme Active Site ◽  
Bond Forming ◽  
State Electron ◽  
Ground State Electron

<p>Stereoselective bond-forming reactions are essential tools in modern organic synthesis. However, catalytic strategies for controlling the stereochemical outcome of radical-mediated C–C bond formation remain underdeveloped.<b> </b>Here, we report an ‘ene’-reductase catalyzed asymmetric hydroalkylation of olefins using α-bromoketones as radical precursors. In these reactions, radical initiation occurs <i>via</i> ground-state electron transfer from the flavin cofactor located within the enzyme active site, representing a mechanistic departure from previous photoenzymatic hydroalkylations. Four rounds of site saturation mutagenesis based on wild-type nicotinamide-dependent cyclohexanone reductase (NCR) were deployed to access a variant capable of catalyzing a cyclization to furnish β-chiral cyclopentanones with high levels of enantioselectivity. Additionally, the wild-type NCR was identified that could catalyze the intermolecular coupling with precise stereochemical control over the radical termination step. This report demonstrates this enzyme family’s catalytic versatility and highlights the opportunity for protein engineering to address reactivity and selectivity challenges in radical biocatalysis. </p>

Ground-state electron transfer in all-polymer donor–acceptor heterojunctions

2020 ◽  
Vol 19 (7) ◽  
pp. 738-744 ◽  
Author(s):  
Kai Xu ◽  
Hengda Sun ◽  
Tero-Petri Ruoko ◽  
Gang Wang ◽  
Renee Kroon ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Ground State ◽  
State Electron ◽  
Donor Acceptor ◽  
Ground State Electron

Ground state electron transfer between TCNE and one or more 16-electron species containing vanadium, osmium, ruthenium or cobalt

1996 ◽  
Vol 251 (1-2) ◽  
pp. 239-248 ◽  
Author(s):  
Frank Baumann ◽  
Martina Heilmann ◽  
Walther Matheis ◽  
Andreas Schulz ◽  
Wolfgang Kaim ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Ground State ◽  
State Electron ◽  
Ground State Electron

Solvent Dynamical Control of Ultrafast Ground State Electron Transfer:  Implications for Class II−III Mixed Valency

2007 ◽  
Vol 129 (42) ◽  
pp. 12772-12779 ◽  
Author(s):  
Benjamin J. Lear ◽  
Starla D. Glover ◽  
J. Catherine Salsman ◽  
Casey H. Londergan ◽  
Clifford P. Kubiak
Keyword(s):  
Electron Transfer ◽  
Ground State ◽  
Class Ii ◽  
Mixed Valency ◽  
State Electron ◽  
Dynamical Control ◽  
Ground State Electron

scholarly journals C–C bond-forming reactions of ground-state aryl halides under reductive activation

Tetrahedron ◽  
2016 ◽  
Vol 72 (48) ◽  
pp. 7875-7887 ◽  
Author(s):  
Katie J. Emery ◽  
Tell Tuttle ◽  
Alan R. Kennedy ◽  
John A. Murphy
Keyword(s):  
Ground State ◽  
Aryl Halides ◽  
Reductive Activation ◽  
Bond Forming ◽  
Bond Forming Reactions
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