42289-52-1Relevant academic research and scientific papers
Preparation of Polyfunctionalized Aromatic Nitriles from Aryl Oxazolines
Hess,Guelen,Alandini,Mourati,Guersoy,Knochel
supporting information, (2021/12/06)
A selective ortho,ortho’-functionalization of readily available aryl oxazolines by two successive magnesiations with sBu2Mg in toluene followed by trapping reactions with electrophiles, such as (hetero)aryl iodides or bromides, iodine, tosyl cyanide, ethyl cyanoformate or allylic bromides (39 examples, 62–99 % yield) is reported. Treatment of these aryl oxazolines with excess oxalyl chloride and catalytic amounts of DMF (50 °C, 4 h) provided the corresponding nitriles (36 examples, 73–99 % yield). Conversions of these nitriles to valuable heterocycles are reported, and a tentative mechanism is proposed.
Nickel- and Palladium-Catalyzed Cross-Coupling Reactions of Organostibines with Organoboronic Acids
Zhang, Dejiang,Le, Liyuan,Qiu, Renhua,Wong, Wai-Yeung,Kambe, Nobuaki
supporting information, p. 3104 - 3114 (2020/12/11)
A strategy for the formation of antimony-carbon bond was developed by nickel-catalyzed cross-coupling of halostibines. This method has been applied to the synthesis of various triaryl- and diarylalkylstibines from the corresponding cyclic and acyclic halostibines. This protocol showed a wide substrate scope (72 examples) and was compatible to a wide range of functional groups such as aldehyde, ketone, alkene, alkyne, haloarenes (F, Cl, Br, I), and heteroarenes. A successful synthesis of arylated stibine 3 a in a scale of 34.77 g demonstrates high synthetic potential of this transformation. The formed stibines (R3Sb) were then used for the palladium-catalyzed carbon–carbon bond forming reaction with aryl boronic acids [R?B(OH)2], giving biaryls with high selectivity, even the structures of two organomoieties (R and R′) are very similar. Plausible catalytic pathways were proposed based on control experiments.
Visible-Light-Promoted Metal-Free Synthesis of (Hetero)Aromatic Nitriles from C(sp3)?H Bonds**
Murugesan, Kathiravan,Donabauer, Karsten,K?nig, Burkhard
supporting information, p. 2439 - 2445 (2020/12/07)
The metal-free activation of C(sp3)?H bonds to value-added products is of paramount importance in organic synthesis. We report the use of the commercially available organic dye 2,4,6-triphenylpyrylium tetrafluoroborate (TPP) for the conversion of methylarenes to the corresponding aryl nitriles via a photocatalytic process. Applying this methodology, a variety of cyanobenzenes have been synthesized in good to excellent yield under metal- and cyanide-free conditions. We demonstrate the scope of the method with over 50 examples including late-stage functionalization of drug molecules (celecoxib) and complex structures such as l-menthol, amino acids, and cholesterol derivatives. Furthermore, the presented synthetic protocol is applicable for gram-scale reactions. In addition to methylarenes, selected examples for the cyanation of aldehydes, alcohols and oximes are demonstrated as well. Detailed mechanistic investigations have been carried out using time-resolved luminescence quenching studies, control experiments, and NMR spectroscopy as well as kinetic studies, all supporting the proposed catalytic cycle.
Integration of borylation of aryllithiums and Suzuki-Miyaura coupling using monolithic Pd catalyst
Nagaki,Hirose,Moriwaki,Mitamura,Matsukawa,Ishizuka,Yoshida
, p. 4690 - 4694 (2016/07/07)
Integration of the preparation of arylboronic esters via aryllithiums and Suzuki-Miyaura coupling using monolithic Pd catalyst without an intentionally added base was achieved. A continuous operation has been done successfully for over 21 hours.
Vapour-phase Chemistry of Arenes. Part 13. Reactivity and Selectivity in the Gas-phase Reactions of Hydroxyl Radicals with Monosubstituted Benzenes at 563 K
Mulder, Peter,Louw, Robert
, p. 1167 - 1174 (2007/10/02)
The reactions of hydroxyl radicals with benzene derivates C6H5Z (Z = H, Me, F, Cl, Br, I, CF3, or CN) have been studied in a flow reactor at 563 K in nitrogen, using the thermolysis of ButOOH as a source of .OH.Under these conditions there are two product-forming pathways.The major one involves hydrogen abstraction to give aryl radicals ZC6H4. (II) as the first step; depending on Z, its displacement to form phenol may also occur.Relative rates for hydrogen abstraction were determined in competition experiments using side-chain hydrogen abstraction from added toluene as a reference.This resulted in the order (for Z =): 1,8(Me), 1.0(H), 0.47(F), 0.29(Cl), 0.34(CF3), 0.20(CN), consonant with the electrophilic nature of .OH.The site selectivity of hydrogen abstractions was determined by scavenging part of the aryl radicals (II) with iodine.A Hammett plot, using ? constants for meta and para positions, led to ρ -1.0.The features of hydrogen abstraction by .OH are discussed and compared with those for the analogous reaction of Cl.The formation of phenol was found to decrease in importance in the order F, Cl, Br, and I.This result is rationalized on a thermochemical kinetic basis.
