scholarly journals Selective, Radical-Free Activation of Benzylic C-H Bonds in Methylarenes

2021 ◽  
Author(s):  
Antony Chan ◽  
Martin Jakoobi ◽  
Yan-Cong Tian ◽  
Chenxu Wang ◽  
Nathan Halcovitch ◽  
...  
Keyword(s):  
Oxidative Addition ◽  
Iridium Complexes ◽  
Mechanistic Studies

We report rare examples of exclusive benzylic C-H oxidative addition in industrially important methylarenes using simple η4-arene iridium complexes. Mechanistic studies showed that coordinatively unsaturated η2-arene intermediates are responsible for...

scholarly journals Controlling Non-Native B12 Reactivity and Catalysis in the Transcription Factor CarH

2021 ◽  
Author(s):  
Xinhang Yang ◽  
Benjamin H. R. Gerroll ◽  
Yuhua Jiang ◽  
Amardeep Kumar ◽  
Yasmine S. Zubi ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Vitamin B12 ◽  
Transcription Regulation ◽  
Bond Cleavage ◽  
Oxidative Addition ◽  
Mechanistic Studies ◽  
Organic Transformations ◽  
Carbon Bond ◽  
Wide Range ◽  
Hydride Elimination

Vitamin B12 derivatives catalyze a wide range of organic transformations, but B12-dependent enzymes are underutilized in biocatalysis relative to other metalloenzymes. In this study, we engineered a variant of the transcription factor CarH, called CarH*, that catalyzes styrene C-H alkylation with improved yield and selectivity relative to B12 itself. While the native function of CarH involves transcription regulation via AdoCbl Co(III)-carbon bond cleavage and β-hydride elimination to generate 4’,5’-didehydroadenosine, CarH*-catalyzed styrene alkylation proceeds via non-native oxidative addition and olefin addition coupled with a native-like β-hydride elimination. Mechanistic studies on this reaction echo findings from earlier studies on AdoCbl homolysis under strong cage conditions to suggest that CarH* can enable non-native radical chemistry with improved selectivity relative to B12 itself. These findings lay the groundwork for the development of B12-dependent enzymes as catalysts for a wide range of non-native transformations.

Oxidative Addition Reactions to Novel Heterotrinuclear Iridium Complexes with Mixed Bridging Ligands. Crystal Structure of [{Ir(.mu.-pz)(.mu.-StBu)I2(CO)[P(OMe)3]}2Pd]

1995 ◽  
Vol 34 (1) ◽  
pp. 111-115 ◽  
Author(s):  
M. Teresa Pinillos ◽  
Anabel Elduque ◽  
Eduardo Martin ◽  
Nuria Navarro ◽  
Fernando J. Lahoz ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Oxidative Addition ◽  
Addition Reactions ◽  
Iridium Complexes ◽  
Bridging Ligands
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