60060-48-2Relevant academic research and scientific papers
Multienzymatic stereoselective reduction of tetrasubstituted cyclic enones to halohydrins with three contiguous stereogenic centers
Brenna, Elisabetta,Colombo, Danilo,Fraaije, Marco W.,Gatti, Francesco G.,Macchi, Piero,Monti, Daniela,Trajkovic, Milos,Venturi, Silvia,Zamboni, Emilio
, p. 13050 - 13057 (2020/11/17)
The asymmetric hydrogenation of conjugated tetrasubstituted alkenes with transition-metal catalysts is a challenging reaction, especially for substrates bearing a halide substituent. We describe a two-step multienzymatic reduction of a series of α-halo β-alkyl tetrasubstituted cyclic enones, affording halohydrins with three contiguous stereogenic centers, in good yield and with a high stereoselectivity. The reduction is catalyzed by a stereospecific ene-reductase (OYE2-3 or NemA) and a highly enantioselective alcohol dehydrogenase (ADH). The use of two enantiodivergent ADHs allows the control of the diastereoselectivity. The absolute stereochemical configurations of the products have been determined from the analysis of single-crystal structures (Flack's parameter). The enantiomeric excess (ee) has been determined by derivatization of the products with (R) Mosher's acid. Lastly, we extended our methodology also to a nonhalogenated substrate: the α-methyl ketoisophorone was reduced by two distinct enantiodivergent ene-reductases (flavin mononucleotide- and F420-dependent), affording each enantiomer of the saturated ketone with ee > 98%.
Halogenation of carbonyl compounds by an ionic liquid, [AcMIm]X, and Ceric Ammonium Nitrate (CAN)
Ranu, Brindaban C.,Adak, Laksmikanta,Banerjee, Subhash
, p. 358 - 362 (2008/02/13)
An ionic liquid, acetylmethylimidazolium halide ([AcMIm]X), in combination with ceric ammonium nitrate promotes halogenations of a wide variety of ketones and 1,3-keto esters at the ?-position. The ionic liquid acts here as reagent as well as reaction medium, and thus the reaction does not require any organic solvent or conventional halogenating agent. The reaction is completely arrested when the radical quencher TEMPO is used. A plausible radical mechanism is also suggested. CSIRO 2007.
Metal-Catalyzed Organic Photoreactions. The Photooxidation of Vinylsilanes and Vinyl Sulfides in the Presence of Iron(III) Chloride, and the Regioselective Synthesis of α-Chloro Ketones
Sato, Tadashi,Tonegawa, Tamotsu,Naoi, Kunio,Murayama, Eigoro
, p. 285 - 286 (2007/10/02)
The irradiation of a pyridine solution of vinylsilanes or vinyl sulfides in the presence of iron(III) chloride under oxygen produced α-chloro ketones, with a carbonyl group at the olefinic carbon originally bearing a silicon or sulfur atom.
