123902-04-5Relevant articles and documents
Photoenzymatic Reductions Enabled by Direct Excitation of Flavin-Dependent "Ene"-Reductases
Sandoval, Braddock A.,Clayman, Phillip D.,Oblinsky, Daniel G.,Oh, Seokjoon,Nakano, Yuji,Bird, Matthew,Scholes, Gregory D.,Hyster, Todd K.
, p. 1735 - 1739 (2021)
Non-natural photoenzymatic reactions reported to date have depended on the excitation of electron donor-acceptor complexes formed between substrates and cofactors within protein active sites to facilitate electron transfer. While this mechanism has unlocked new reactivity, it limits the types of substrates that can be involved in this area of catalysis. Here we demonstrate that direct excitation of flavin hydroquinone within "ene"-reductase active sites enables new substrates to participate in photoenzymatic reactions. We found that by using photoexcitation these enzymes gain the ability to reduce acrylamides through a single electron transfer mechanism.
Anodic Amide Oxidations in the Presence of Electron-Rich Phenyl Rings: Evidence for an Intramolecular Electron-Transfer Mechanism
Moeller, Kevin D.,Wang, Po W.,Tarazi, Sharif,Marzabadi, Mohammad R.,Wong, Poh Lee
, p. 1058 - 1067 (2007/10/02)
The anodic oxidations of amides in the presence of mono-, di-, and trialkoxyphenyl rings were examined.Although literature reduction potentials suggest that these oxidations would lead to either selective aromatic ring oxidation or mixtures, the chemoselectivity of the reactions was found to be dependent on the substitution pattern of the phenyl ring.For example, the anodic oxidations of ((3-methoxyphenyl)acetyl)pyrrolidine, ((2-methoxyphenyl)acetyl)pyrrolidine, ((3-methoxy-4-(pivaloyloxy)phenyl)acetyl)pyrrolidine, and ((3,5-dimethoxy-4-(pivaloyloxy)phenyl)acetyl)pyrrolidine all led to selective methoxylation of the pyrrolidine ring.The anodic oxidations of ((4-methoxyphenyl)acetyl)pyrrolidine and ((3,4-dimethoxyphenyl)acetyl)pyrrolidine led to selective methoxylation of the benzylic carbon.Mechanistic studies indicate that both amide and aryl oxidation processes compete under the reaction conditions, but that intramolecular electron transfer leads to the selective formation of products.Evidence for this mechanism was obtained by examining the cyclic voltammogram of ((3-methoxyphenyl)acetyl)pyrrolidine, competition studies, and the preparative electrolysis of ((4-methoxyphenyl)dimethylacetyl)pyrrolidine.The methoxylated amides were cyclized to form tricyclic amides using titanium tetrachloride.
