101-82-6Relevant articles and documents
LIGAND COUPLING REACTION ON THE PHOSPHORUS ATOM
Uchida, Yuzuru,Onoue, Katsumi,Tada, Nobuaki,Nagao, Fumio
, p. 567 - 570 (1989)
Phosphine oxides bearing two or three 2-pyridyl groups were found to react with organometallic compounds affording 2,2'-bipyridyl, 2-substituted pyridines and pyridine in substantial yields.Both ligand exchange and ligand coupling appear to take place within the penta-coordinated phosphorus intermediates formed incipiently.
CONVERSION OF HETEROCYCLIC N-OXIDES INTO α-ALKYLATED HETEROCYCLES. TRIMETHYLSILANOL AS LEAVING GROUP -IV.
Vorbrueggen, Helmut,Krolikiewicz, Konrad
, p. 889 - 890 (1983)
Aromatic heterocyclic N-oxides are readily converted into α-alkylated heterocycles by allyl-or benzyltrimethylsilane and fluoride ion.
Metal-Free Halogen(I) Catalysts for the Oxidation of Aryl(heteroaryl)methanes to Ketones or Esters: Selectivity Control by Halogen Bonding
Guha, Somraj,Sekar, Govindasamy
, p. 14171 - 14182 (2018)
Metal-free halogen(I) catalysts were used for the selective oxidation of aryl(heteroaryl)methanes [C(sp3)?H] to ketones [C(sp2)=O] or esters [C(sp3)?O]. The synthesis of ketones was performed with a catalytic amount of NBS in DMSO solvent. Experimental studies and density functional theory (DFT) calculations supported the formation of halogen bonding (XB) between the heteroarene and N-bromosuccinimide, which enabled imine–enamine tautomerism of the substrates. No additional activator was required for this crucial step. Isotope-labeling and other supporting experiments suggested that a Kornblum-type oxidation with DMSO and aerobic oxygenation with molecular oxygen took place simultaneously. A background XB-assisted electron transfer between the heteroarenes and halogen(I) catalysts was responsible for the formation of heterobenzylic radicals and, thus, the aerobic oxygenation. For selective acyloxylation (ester formation), a catalytic amount of iodine was employed with tert-butyl hydroperoxide in aliphatic carboxylic acid solvent. Several control reactions, spectroscopic studies, and Time-Dependent Density Functional Theory (TD–DFT) calculations established the presence of acetyl hypoiodite as an active halogen(I) species in the acetoxylation process. With the help of a selectivity study, for the first time we report that the strength of the XB interaction and the frontier orbital mixing between the substrates and acyl hypoiodites determined the extent of the background electron-transfer process and, thus, the selectivity of the reaction.
A novel iodide-catalyzed reduction of nitroarenes and aryl ketones with H3PO2 or H3PO3: Its application to the synthesis of a potential anticancer agent
Wu, George G.,Chen, Frank X.,LaFrance, Danny,Liu, Zhijian,Greene, Scott G.,Wong, Yee-Shing,Xie, Ji
, p. 5220 - 5223 (2011)
A novel iodide-catalyzed reduction method using hypophosphorous and/or phosphorus acids was developed to reduce both diaryl ketones and nitroarenes chemoselectively in the presence of chloro and bromo substituents in high yield. This efficient and practical method has been successfully applied to a large scale production of a potential anticancer agent
A novel reduction of pyridinemethanols by samarium diiodide
Kato, Yoshiaki,Mase, Toshiaki
, p. 8823 - 8826 (1999)
An efficient synthesis of alkylpyridine derivatives by SmI2 mediated deoxygenation of pyridinemethanol derivatives is described.
Palladium-catalyzed coupling reactions of (ArCH2)Ti(O-i-Pr) 3 with aromatic or heteroaromatic bromides
Chang, Shu-Ting,Li, Qinghan,Chiang, Ruei-Tang,Gau, Han-Mou
, p. 3956 - 3962 (2012)
Three benzyltitanium compounds of (ArCH2)Ti(O-i-Pr)3 (Ar = Ph (1a), 4-MeOC6H4 (1b), 4-FC6H 4 (1c)) were prepared and used as benzyl nucleophiles for coupling reactions with aromatic or heteroaromatic bromides. The simple catalytic system of 1 mol % Pd(OAc)2 and 2 mol % PCy3 worked efficiently for a wide variety of aromatic bromides, producing diarylmethanes in good to excellent yields of up to 96%. Coupling reactions of hindered aromatic bromides or aromatic bromides containing electron-withdrawing substituents were slower over longer reaction times of 3-6 h. Reactions of heteroaromatic bromides of bromopyridines, bromofurans, or bromothiophenes with benzyl reagents of 1a or 1b required either longer reaction times of 12-24 h or a higher reaction temperature of 80 °C, producing pyridyl-, furyl-, and thienyl-arylmethanes in moderate yields.
Palladium-catalyzed regioselective benzylation-annulation of pyridine N -oxides with toluene derivatives via multiple c-h bond activations: Benzylation versus arylation
Kianmehr, Ebrahim,Faghih, Nasser,Khan, Khalid Mohammed
, p. 414 - 417 (2015)
A palladium-catalyzed cross-dehydrogenative coupling (CDC) reaction of pyridine N-oxides with toluenes has been developed that operates under mild conditions. 2-Benzylpyridines can be obtained directly by this method via a CDC reaction between unactivated toluenes and pyridine N-oxides. In addition, azafluorene N-oxides, of value for future medicinal chemistry applications, can be obtained successfully by this procedure via four tandem C-H bond activations.
Acylation of 2-benzylpyridine N-oxides and subsequent in situ [3,3]-sigamatropic rearrangement reaction
Antilla, Jon C.,Jing, Hua-qing,Li, Hong-liang
supporting information, (2020/09/22)
An effective method for the acylation of 2-benzylpyridine N-oxides and their fast in situ [3,3]-sigmatropic rearrangement was reported. This transformation has a wide substrate scope under mild conditions, giving moderate to excellent yields. The application for the synthesis of chiral phenyl-2-pyridylmethanol products was briefly explored. Furthermore, an interesting example of tandem substitution and in situ [3,3]-sigamatropic rearrangement of 2-benzylpyridine N-oxide with benzenecarboximidoyl chloride was reported.
Catalytic Selective Metal-Free Cross-Coupling of Heteroaromatic N-Oxides with Organosilanes
Puthanveedu, Mahesh,Polychronidou, Vasiliki,Antonchick, Andrey P.
supporting information, p. 3407 - 3411 (2019/05/10)
A metal-free, regioselective C-H functionalization of heteroaromatic N-oxides has been developed. The method enables the synthesis of various benzylated and alkynylated N-heterocycles in a transition-metal-free manner employing organosilanes as coupling partners. The unanticipated reactivity has been exploited for the synthesis of a number of symmetrical disubstituted acetylenes from ethynyltrimethylsilane via carbon-silicon bond metathesis.
Ligand-Free Iridium-Catalyzed Dehydrogenative ortho C?H Borylation of Benzyl-2-Pyridines at Room Temperature
Yang, Yuhuan,Gao, Qian,Xu, Senmiao
supporting information, p. 858 - 862 (2019/01/04)
A convenient and ligand-free iridium-catalyzed dehydrogenative ortho C?H borylation of benzyl-2-pyridines has been developed. The reaction proceeds smoothly at room temperature using pinacolborane as a borylating reagent in the presence of catalytic amount of [IrOMe(COD)]2. The reaction is compatible with many functional groups, providing a vast array of ortho borylated products in moderate to excellent yields with excellent selectivities. (Figure presented.).
