64967-44-8Relevant academic research and scientific papers
Chromium(II)-Catalyzed Diastereoselective and Chemoselective Csp2-Csp3 Cross-Couplings Using Organomagnesium Reagents
Li, Jie,Ren, Qianyi,Cheng, Xinyi,Karaghiosoff, Konstantin,Knochel, Paul
supporting information, p. 18127 - 18135 (2019/11/19)
A simple protocol for performing chromium-catalyzed highly diastereoselective alkylations of arylmagnesium halides with cyclohexyl iodides at ambient temperature has been developed. Furthermore, this ligand-free CrCl2 enables efficient electrophilic alkenylations of primary, secondary, and tetiary alkylmagnesium halides with readily available alkenyl acetates. Moreover, this chemoselective C-C coupling reaction with stereodefined alkenyl acetates proceeds in a stereoretentive fashion. A wide range of functional groups on alkyl iodides and alkenyl acetates are well tolerated, thus furnishing functionalized Csp2-Csp3 coupling products in good yields and high diastereoselectivity. Detailed mechanistic studies suggest that the in situ generated low-valent chromium(I) species might be the active catalyst for these Csp2-Csp3 cross-couplings.
Preparation of Imidazole Derivatives via Bisfunctionalization of Alkynes Catalyzed by Ruthenium Carbonyl
Chen, Yue-Peng,Gu, Ling-Hui,He, Ling,Luo, Yang,Ruan, Yi-Tong,Yang, Ze
, p. 3520 - 3528 (2019/09/07)
A one-step, oxidative bisfunctionalization of alkynes to generate cis -enediol diacetates catalyzed by ruthenium carbonyl (triruthenium dodecacarbonyl) is presented. The reaction was performed using the alkyne, (diacetoxyiodo)benzene, Ru 3 (CO) 12 as the catalyst, and toluene as the solvent at 100 °C to give the cis -enediol diacetates in up to 82percent yields. This method overcomes the shortcomings of existing methods, such as tedious reaction steps, substrate limitations, and the use of toxic reagents. Furthermore, the reaction of module cis -enediol diacetates with ammonium carbonate [(NH 4) 2 CO 3 ] in an alcohol solvent gave imidazole derivatives in 37-84percent yields, thus providing a simple and mild new method for the synthesis of imidazole compounds.
Enzyme Promiscuity as a Remedy for the Common Problems with Knoevenagel Condensation
Koszelewski, Dominik,Ostaszewski, Ryszard
, p. 10156 - 10164 (2019/07/09)
A new protocol based on lipase-catalyzed tandem reaction toward α,β-enones/enoesters is presented. For the synthesis of the desired products the tandem process based on enzyme-catalyzed hydrolysis and Knoevenagel reaction starting from enol acetates and aldehyde is developed. The relevant impact of the reaction conditions including organic solvent, enzyme type, and temperature on the course of the reaction was revealed. It was shown that controllable release of the active methylene compound from the corresponding enol carboxylate ensured by enzymatic reaction diminishes significantly the formation of the unwanted co-products. Furthermore, this protocol was extended by including a second tandem chemoenzymatic transformation engaging various aldehyde precursors. After a careful optimization of the reaction conditions, the target products were obtained with yields up to 86 % and with excellent E/Z-selectivity.
Gold(I)-catalyzed addition of carboxylic acids to alkynes
Chary, Bathoju Chandra,Kim, Sunggak
supporting information; experimental part, p. 7928 - 7931 (2011/02/23)
Au(I)-catalyzed hydroacyloxylation of alkynes with carboxylic acids is described. PPh3AuCl/AgPF6 catalyst affords the Markonikov addition products, whereas PPh3AuCl/AgOTf catalyst gives the more stable isomerized products
