62119-81-7Relevant articles and documents
Markovnikov Wacker-Tsuji Oxidation of Allyl(hetero)arenes and Application in a One-Pot Photo-Metal-Biocatalytic Approach to Enantioenriched Amines and Alcohols
Albarrán-Velo, Jesús,Gotor-Fernández, Vicente,Lavandera, Iván
, p. 4096 - 4108 (2021/08/19)
The Wacker-Tsuji aerobic oxidation of various allyl(hetero)arenes under photocatalytic conditions to form the corresponding methyl ketones is presented. By using a palladium complex [PdCl2(MeCN)2] and the photosensitizer [Acr-Mes]ClO4 in aqueous medium and at room temperature, and by simple irradiation with blue led light, the desired carbonyl compounds were synthesized with high conversions (>80%) and excellent selectivities (>90%). The key process was the transient formation of Pd nanoparticles that can activate oxygen, thus recycling the Pd(II) species necessary in the Wacker oxidative reaction. While light irradiation was strictly mandatory, the addition of the photocatalyst improved the reaction selectivity, due to the formation of the starting allyl(hetero)arene from some of the obtained by-products, thus entering back in the Wacker-Tsuji catalytic cycle. Once optimized, the oxidation reaction was combined in a one-pot two-step sequential protocol with an enzymatic transformation. Depending on the biocatalyst employed, i. e. an amine transaminase or an alcohol dehydrogenase, the corresponding (R)- and (S)-1-arylpropan-2-amines or 1-arylpropan-2-ols, respectively, could be synthesized in most cases with high yields (>70%) and in enantiopure form. Finally, an application of this photo-metal-biocatalytic strategy has been demonstrated in order to get access in a straightforward manner to selegiline, an anti-Parkinson drug. (Figure presented.).
Tuning lipase-catalysed kinetic resolution of 2-substituted thiophenes and furans: A scalable chemoenzymatic route to masked γ-bis-oxo-alcohols
Ferreira, Dartagnan S.P.,Ferreira, Jeiely G.,Filho, Everaldo F.S.,Princival, Jefferson L.
, p. 37 - 45 (2016/02/18)
The demand for greener and applicable approaches aiming at the synthesis of optically active compounds as single enantiomers has seen a significant growth worldwide. Since most of the chemically synthesized compounds are produced as racemates their kinetic resolution has been of great interest. For this purpose a number of chemo-enzymatic approaches were proposed. One of such approaches, the use of isolated lipases, is a well-established alternative. Herein we report the kinetic resolutions of 2-Substituted five-membered heteroaromatic rings. By optimizing the reaction conditions it was possible to produce (2-hydroxy)-2-substituted furans and thiophenes in high enantiomeric ratio (E > 200). Thus, racemic mixtures of compounds with slight structural differences were resolved. The current chemo-enzymatic strategy has been applied to a scalable approach leading to the formation of the enantiopure (S)-2i a well-known building block used for the synthesis of bioactive natural compounds.
Microbial deracemization of 1-Aryl and 1-heteroaryl secondary alcohols
Allan,Carnell
, p. 6495 - 6497 (2007/10/03)
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