17669-30-6Relevant articles and documents
Electrochemical Synthesis of Isoxazolines: Method and Mechanism
Holman, Samuel D. L.,Wills, Alfie G.,Fazakerley, Neal J.,Poole, Darren L.,Coe, Diane M.,Berlouis, Leonard A.,Reid, Marc
, (2022/02/19)
An electrochemical method for the green and practical synthesis of a broad range of substituted isoxazoline cores is presented. Both aryl and more challenging alkyl aldoximes are converted to the desired isoxazoline in an electrochemically enabled regio- and diastereoselective reaction with electron-deficient alkenes. Additionally, in-situ reaction monitoring methods compatible with electrochemistry equipment have been developed in order to probe the reaction pathway. Supporting analyses from kinetic (time-course) modelling and density functional theory support a stepwise, radical-mediated mechanism, and discounts hypothesised involvement of closed shell [3+2] cycloaddition pathways.
Pd Catalysis in Cyanide-Free Synthesis of Nitriles from Haloarenes via Isoxazolines
Maestri, Giovanni,Ca?eque, Tatiana,Della Ca, Nicola,Derat, Etienne,Catellani, Marta,Chiusoli, Gian Paolo,Malacria, Max
supporting information, p. 6108 - 6111 (2016/12/09)
A method to obtain aryl nitriles from the corresponding halides by Pd catalysis, in the absence of any cyanide source, is reported. The reaction of an aryl halide, ethyl nitroacetate, and an olefin readily delivers an aromatic nitrile. A variety of aryl iodides/bromides have been converted into the corresponding cyanoarenes in fair to excellent yields. The reaction likely involves the following steps: (a) Pd-catalyzed α-arylation of ethyl nitroacetate; (b) nitrile oxide formation; (c) [3 + 2]-cycloaddition with an olefin to provide an isoxazoline; (d) isoxazoline cleavage to benzonitrile formation.
Visible-light-mediated generation of nitrile oxides for the photoredox synthesis of isoxazolines and isoxazoles
Svejstrup, Thomas D.,Zawodny, Wojciech,Douglas, James J.,Bidgeli, Damon,Sheikh, Nadeem S.,Leonori, Daniele
, p. 12302 - 12305 (2016/10/22)
Visible-light photoredox catalysis enables the synthesis of biologically relevant isoxazolines and isoxazoles from hydroxyimino acids. The process shows broad functional group compatibility and mechanistic and computational studies support a visible-light-mediated generation of nitrile oxides by two sequential oxidative single electron transfer processes.
Diastereoselective 1,3-dipolar cycloadditions of both electronically modified phenyl-nitrile oxides and stilbenes
Romanski, Jan,Nowak, Piotr,Maksymiuk, Anna,Chapuis, Christian,Jurczak, Janusz
, p. 23105 - 23118 (2013/11/19)
Menthyl carboxyloyl nitrile oxide addition is less selective for (E)-stilbene (12% d.e.) than for its corresponding (1R)-8-phenyl-menthyl (38% d.e.) or (2R)-bornane[10,2]sultam (48% d.e.) analogues. This lower selectivity is also observed when the chiral auxiliary is placed on the dipolarophile, as demonstrated by the [3 + 2] cycloadditions of p-NO2-phenyl nitrile oxide to acryloyl derivatives of (1R)-menthol (4% d.e.) and (2R)-bornane[10,2] sultam (60% d.e.). We managed to increase these diastereoselectivities by taking advantage of the Tolbert and Ali co-operative influence of two prosthetic groups, as seen in phenyl nitrile oxide addition to the bis-fumaroyl derivatives of (1R)-menthol (30% d.e.) and (2R)-bornane[10,2]sultam (98% d.e.). In the specific case of the N-acryloyl bornane[10,2]sultam, we found evidence for a small predictable negative influence of electronically deficient para-substituted phenyl nitrile oxides on diastereoselectivity (p-Me 2N, 72% d.e.; p-F, 65% d.e.; p-NO2, 60% d.e.). This may be explained by the participation of the more reactive but thermodynamically less stable syn-s-cis conformer in the reaction pathway, given its smaller difference of calculated energies in the corresponding transition states. Such an explanation is further supported by the negative influence of either a polar solvent, stabilizing these more polar transition states (phenyl nitrile oxide in hexane, 76% d.e.; CH2Cl2, 71% d.e.; MeCN, 67% d.e.), or a chelating Lewis acid (MgCl2, 66% d.e.).
Conversion of oximes to carbonyl compounds by triscetylpyridinium tetrakis(oxodiperoxotungsto) phosphate (PCWP)-mediated oxidation with hydrogen peroxide
Ballistreri, Francesco P.,Chiacchio, Ugo,Rescifina, Antonio,Tomaselli, Gaetano,Toscano, Rosa M.
, p. 1230 - 1237 (2008/12/21)
Aromatic and aliphatic oximes have been deoximated in chloroform-water to the corresponding aldehydes with dilute hydrogen peroxide and triscetylpyridinium tetrakis (oxodiperoxotungsto) phosphate as catalyst. The presence of dipolarophiles in the reaction mixtures allows a competitive reaction that converts oximes into isoxazole and isoxazoline derivatives via the intermediate formation of nitrile oxide species.
