2323-36-6Relevant 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
supporting information, 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.).
Preparation method of selegiline
-
Paragraph 0058; 0062-0065; 0069-0072; 0076-0078, (2019/08/14)
The invention provides a preparation method of selegiline. The method comprises the steps of carrying out an acyl chlorination reaction on a compound (i), carrying out an acylation reaction on the compound (i) and benzene, and carrying out a propargylation reaction after carbonyl reduction and deacylation to obtain selegiline, wherein in the compound (i), R represents methyl or ethyl or trifluoromethyl or phenyl or benzyl. According to the method, an acyl-D-N-methylalanine compound is used as a raw material and subjected to acylation, carbonyl reduction, the deacylation reaction and the propargylation reaction to obtain the selegiline, not only is the raw material simple and easy to obtain, but also there are few reaction steps, the operation is simple and convenient, and dangerous or high-price reagent raw materials do not need to be used. Meanwhile, according to the method, chiral resolution of an intermediate or a final product is not needed, the ee value of the product is high, theyield is high, and the method is suitable for large-scale and industrial production.
A concise enantioselective synthesis of (R)-selegiline, (S)-benzphetamine and formal synthesis of (R)-sitagliptin via electrophilic azidation of chiral imide enolates
Dey, Soumen,Sudalai, Arumugam
, p. 67 - 72 (2015/02/02)
A concise and high yielding enantioselective synthesis of (R)-selegiline, an anti-Parkinson's drug, (S)-benzphetamine, an anti-obesity agent, and (S)-sitagliptin, an anti-diabetic drug has been described starting from commercially available starting materials employing Evans' electrophilic azidation of chiral imide enolates as a key chiral inducing step, which proceeds in a highly diastereoselective manner (>99%).
