129830-97-3Relevant articles and documents
Enantioselective biocatalytic reduction of non-protected hydroxyacetophenones
Neupert, Adrian,Ress, Tina,Wittmann, Jrgen,Hummel, Werner,Grger, Harald
, p. 337 - 340 (2010)
Direct enantioselective reduction of -, - and -hydroxyacetophenone without protection of the hydroxy moiety was carried out in the presence of (R)- and (S)-alcohol dehydrogenases as bio-catalysts. Whereas reduction of -hydroxyacetophenone gave only low to
Synthesis of (S)-1-(4-hydroxyphenyl)alcohols by eugenol dehydrogenase from Pseudomonas fluorescens E118
Wieser, Marco,Furukawa, Hirotaka,Morita, Hiroshi,Yoshida, Toyokazu,Nagasawa, Toru
, p. 1627 - 1630 (1999)
(S)-1-(4-Hydroxyphenyl)ethanol and (S)-1-(4-hydroxyphenyl)propanol were synthesized with enantiomeric excesses of 96.6% and 95.2%, respectively, from the corresponding 4-alkylphenols by eugenol dehydrogenase from Pseudomonas fluorescens E118. The enantios
The reaction mechanism of chiral hydroxylation of p -OH and p -NH 2 substituted compounds by ethylbenzene dehydrogenase
Dudzik, Agnieszka,Kozik, Bartlomiej,Tataruch, Mateusz,Wojcik, Anna,Knack, Daniel,Borowski, Tomasz,Heider, Johann,Witko, Malgorzata,Szaleniec, MacIej
, p. 775 - 786 (2013)
Ethylbenzene dehydrogenase (EbDH; enzyme commission (EC) number: 1.17.99.2) is a unique biocatalyst that hydroxylates alkylaromatic and alkylheterocyclic compounds to (S)-secondary alcohols under anaerobic conditions. The enzyme exhibits a high promiscuity catalyzing oxidation of over 30 substrates, inter alia, para-substituted alkylphenols and alkylanilines. Secondary alcohols with OH and NH2 substituents in the aromatic ring are highly valuable synthons for many biologically active compounds in the fine chemical industry. EbDH hydroxylates most of the studied compounds highly enantioselectively, except for five substrates that harbour OH and NH2 groups in the para position, which exhibit a significant decrease in the percent enantiomeric excess (% ee). This phenomenon is inconsistent with the previously suggested enzyme mechanism, but it may be linked to a stabilization of the carbocation intermediate by deprotonation of the OH or NH2 substituent in the active site that yields a transient quinone (imine) ethide species. This would initiate an alternative reaction pathway involving the addition of a water molecule to a C=C double bond. This hypothesis was cross-validated by density functional theory (DFT) cluster modelling of the alternative reaction pathway with 4-ethylphenol, as well as by experimental assessment of the pH dependency of enantiomeric excesses. The results reported herein suggest that the alternative reaction pathway may significantly contribute to the overall reaction if the carbocation intermediates are stabilized by deprotonation.
An Enantioconvergent Benzylic Hydroxylation Using a Chiral Aryl Iodide in a Dual Activation Mode
Abazid, Ayham H.,Clamor, Nils,Nachtsheim, Boris J.
, p. 8042 - 8048 (2020/09/21)
The application of a triazole-substituted chiral iodoarene in a direct enantioselective hydroxylation of alkyl arenes is reported. This method allows the rapid synthesis of chiral benzyl alcohols in high yields and stereocontrol, despite its nontemplated nature. In a cascade activation consisting of an initial irradiation-induced radical C-H-bromination and a consecutive enantioconvergent hydroxylation, the iodoarene catalyst has a dual role. It initiates the radical bromination in its oxidized state through an in-situ-formed bromoiodane and in the second, Cu-catalyzed step, it acts as a chiral ligand. This work demonstrates the ability of a chiral aryl iodide catalyst acting both as an oxidant and as a chiral ligand in a highly enantioselective C-H-activating transformation. Furthermore, this concept presents an enantioconvergent hydroxylation with high selectivity using a synthetic catalyst.
Multienzyme One-Pot Cascade for the Stereoselective Hydroxyethyl Functionalization of Substituted Phenols
Payer, Stefan E.,Pollak, Hannah,Schmidbauer, Benjamin,Hamm, Florian,Juri?i?, Filip,Faber, Kurt,Glueck, Silvia M.
, p. 5139 - 5143 (2018/09/13)
The operability and substrate scope of a redesigned vinylphenol hydratase as a single biocatalyst or as part of multienzyme cascades using either substituted coumaric acids or phenols as stable, cheap, and readily available substrates are reported.
