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Search for "C–H activation" in Full Text gives 148 result(s) in Beilstein Journal of Organic Chemistry.

Cationic Pd(II)-catalyzed C–H activation/cross-coupling reactions at room temperature: synthetic and mechanistic studies

  • Takashi Nishikata,
  • Alexander R. Abela,
  • Shenlin Huang and
  • Bruce H. Lipshutz

Beilstein J. Org. Chem. 2016, 12, 1040–1064, doi:10.3762/bjoc.12.99

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  • Takashi Nishikata Alexander R. Abela Shenlin Huang Bruce H. Lipshutz Department of Chemistry & Biochemistry, University of California, Santa Barbara, CA 93106, USA 10.3762/bjoc.12.99 Abstract Cationic palladium(II) complexes have been found to be highly reactive towards aromatic CH activation of
  • arylureas at room temperature. A commercially available catalyst [Pd(MeCN)4](BF4)2 or a nitrile-free cationic palladium(II) complex generated in situ from the reaction of Pd(OAc)2 and HBF4, effectively catalyzes CH activation/cross-coupling reactions between aryl iodides, arylboronic acids and acrylates
  • streamlined and efficient synthesis of boscalid, an agent produced on the kiloton scale annually and used to control a range of plant pathogens in broadacre and horticultural crops. Mechanistic investigations led to a proposed catalytic cycle involving three steps: (1) CH activation to generate a cationic
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Published 20 May 2016

Enantioselective carbenoid insertion into C(sp3)–H bonds

  • J. V. Santiago and
  • A. H. L. Machado

Beilstein J. Org. Chem. 2016, 12, 882–902, doi:10.3762/bjoc.12.87

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  • is an important tool for the synthesis of complex molecules due to the high control of enantioselectivity in the formation of stereogenic centers. This paper presents a brief review of the early issues, related mechanistic studies and recent applications on this chemistry area. Keywords: CH
  • activation; chiral catalysis; diazo compounds; total synthesis; Introduction One of the major challenges met in organic synthesis is the formation of carbon–carbon bonds, in particular in a stereoselective way. Nucleophilic substitution reactions, radical reactions, cross-coupling reactions and the Heck
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Published 04 May 2016

Muraymycin nucleoside-peptide antibiotics: uridine-derived natural products as lead structures for the development of novel antibacterial agents

  • Daniel Wiegmann,
  • Stefan Koppermann,
  • Marius Wirth,
  • Giuliana Niro,
  • Kristin Leyerer and
  • Christian Ducho

Beilstein J. Org. Chem. 2016, 12, 769–795, doi:10.3762/bjoc.12.77

Graphical Abstract
  • deprotection led to the target compound (+)-caprazol (19) [90][92]. For the synthesis of muraymycins, Ichikawa, Matsuda et al. furthermore developed a new route towards the epicapreomycidine-containing urea dipeptide unit via CH activation (Scheme 3) [96][97]. For this purpose, the commercially available δ-N
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Published 22 Apr 2016

Opportunities and challenges for direct C–H functionalization of piperazines

  • Zhishi Ye,
  • Kristen E. Gettys and
  • Mingji Dai

Beilstein J. Org. Chem. 2016, 12, 702–715, doi:10.3762/bjoc.12.70

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  • for organic small-molecule functionalization [56][57][58]. One important application of photoredox catalysis is direct sp3 CH activation and functionalization [59][60][61]. Among the recent advances, direct photoredox redox CH activation of the α-position of amines has been an efficient and
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Published 13 Apr 2016

Base metal-catalyzed benzylic oxidation of (aryl)(heteroaryl)methanes with molecular oxygen

  • Hans Sterckx,
  • Johan De Houwer,
  • Carl Mensch,
  • Wouter Herrebout,
  • Kourosch Abbaspour Tehrani and
  • Bert U. W. Maes

Beilstein J. Org. Chem. 2016, 12, 144–153, doi:10.3762/bjoc.12.16

Graphical Abstract
  • ) could be obtained in 92% yield. In contrast to the two former cases, 4-(4-chlorobenzyl)pyrimidine (5e) could neither be oxidized at 100 °C nor at 130 °C. Competitive CH activation of the 2 position is presumed to be the reason for this observation. Blocking this position by a methyl group (5f
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Published 27 Jan 2016

A journey in bioinspired supramolecular chemistry: from molecular tweezers to small molecules that target myotonic dystrophy

  • Steven C. Zimmerman

Beilstein J. Org. Chem. 2016, 12, 125–138, doi:10.3762/bjoc.12.14

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  • , Darryl Rideout (coincidentally a Madison West High School classmate), Alanna Schepartz, Alan Schwabacher, George Trainor, Craig Wilcox, and Jeff Winkler. Ron Breslow had broad interests, with projects ranging from developing artificial enzymes, to novel anti-aromatic compounds, to remote CH activation
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Published 25 Jan 2016

Pyridylidene ligand facilitates gold-catalyzed oxidative C–H arylation of heterocycles

  • Kazuhiro Hata,
  • Hideto Ito,
  • Yasutomo Segawa and
  • Kenichiro Itami

Beilstein J. Org. Chem. 2015, 11, 2737–2746, doi:10.3762/bjoc.11.295

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  • be a key step in the catalytic cycle consisting of transmetalation with arylsilane, CH activation and reductive elimination [69]. While gold(I) complexes bearing various ligands are used as gold(III) precursors, it remains unclear whether ligands can still coordinate to the gold center or not under
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Published 28 Dec 2015

Recent advances in copper-catalyzed C–H bond amidation

  • Jie-Ping Wan and
  • Yanfeng Jing

Beilstein J. Org. Chem. 2015, 11, 2209–2222, doi:10.3762/bjoc.11.240

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  • ideal model of modern organic synthesis, the direct functionalization of inactivated C–H bonds has been proved to be a promising tool to enable atom and step economical synthesis. Inspired by the splendid advances that have taken place in the chemistry of CH activation, the synthesis of amides has
  • to be capable of catalyzing the C–H amidation reactions, copper is particularly advantageous because of the low cost, low toxicity and broad tolerance of copper catalysts. Therefore, the present review summarizes the advances on the copper-catalyzed CH activation-based amidation (including related
  • bond was not favored. More notably, the exploration on the reaction mechanism disclosed that the activation of the alkyl C–H bond was initiated by the tert-butoxy radical (Scheme 6). Inspired by the alkane CH activation, Yu and Cheng et al. [51] discovered that directly heating amides in cyclohexane
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Published 17 Nov 2015

Half-sandwich nickel(II) complexes bearing 1,3-di(cycloalkyl)imidazol-2-ylidene ligands

  • Johnathon Yau,
  • Kaarel E. Hunt,
  • Laura McDougall,
  • Alan R. Kennedy and
  • David J. Nelson

Beilstein J. Org. Chem. 2015, 11, 2171–2178, doi:10.3762/bjoc.11.235

Graphical Abstract
  • has also been reported to trigger spontaneous CH activation upon coordination to Rh(I) and Ir(I) complexes, leading to 14 electron Rh(III) and Ir(III) species [24][25]. While the methodology applied to ICy worked for IDD (Scheme 3b), repeated attempts to isolate the It-Bu analogue were unsuccessful
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Published 12 Nov 2015

C–H bond halogenation catalyzed or mediated by copper: an overview

  • Wenyan Hao and
  • Yunyun Liu

Beilstein J. Org. Chem. 2015, 11, 2132–2144, doi:10.3762/bjoc.11.230

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  • the conventional electrophilic halogenation of arenes, the site selectivity was a main challenge and mixed haloarene products were frequently obtained. In 2006, Yu and co-workers [32] first realized the selective o-halogenation of pyridine-2-ylbenzenes 1 via CH activation in a copper/O2 system. As
  • -functionalized arene dimerization [37]. Besides the issue of selectivity, another major challenge in the DG-assisted CH activation lied in the removal of the DG, which undermined the efficiency of the synthetic procedure. To alternate the hardly removable DG of the pyridine ring, Carretero and co-workers [38
  • convert smoothly (Scheme 24). Besides catalyzing the halogenation of inactive alkane substrates via a typical CH activation, copper catalysis also exhibited important application in the electrophilic halogenation of some active methylene substrates such as ketones or esters. Although these active
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Published 09 Nov 2015

Active site diversification of P450cam with indole generates catalysts for benzylic oxidation reactions

  • Paul P. Kelly,
  • Anja Eichler,
  • Susanne Herter,
  • David C. Kranz,
  • Nicholas J. Turner and
  • Sabine L. Flitsch

Beilstein J. Org. Chem. 2015, 11, 1713–1720, doi:10.3762/bjoc.11.186

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  • monooxygenases are useful biocatalysts for CH activation, and there is a need to expand the range of these enzymes beyond what is naturally available. A panel of 93 variants of active self-sufficient P450cam[Tyr96Phe]-RhFRed fusion enzymes with a broad diversity in active site amino acids was developed by
  • hydroxylations. Keywords: active site mutagenesis; biotransformation; CH activation; cytochrome P450cam monooxygenase; hydroxylation; Introduction Selective CH activation and oxyfunctionalisation of hydrocarbons offers a route to chiral alcohols and other industrially important synthetic building blocks from
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Published 22 Sep 2015

The facile construction of the phthalazin-1(2H)-one scaffold via copper-mediated C–H(sp2)/C–H(sp) coupling under mild conditions

  • Wei Zhu,
  • Bao Wang,
  • Shengbin Zhou and
  • Hong Liu

Beilstein J. Org. Chem. 2015, 11, 1624–1631, doi:10.3762/bjoc.11.177

Graphical Abstract
  • scaffold has been developed by means of a copper-mediated cascade C–H/C–H coupling and intramolecular annulations and a subsequent facile hydrazinolysis. This CH activation transformation proceeds smoothly with wide generality, good functional tolerance and high stereo- and regioselectivity under mild
  • conditions. Through the removal of the directing group, the resulting moiety could easily be transformed into the phthalazin-1(2H)-one scaffold, which is known to be a privileged moiety and a bioactive nucleus in pharmaceuticals. Keywords: CH activation; copper; phthalazin-1(2H)-one; Introduction The
  • for the construction of the phthalazin-1(2H)-one scaffold. During the last decade, the transition metal-mediated CH activation reaction has emerged as one of the most important and powerful methodologies for the formation of carbon–carbon bonds in a single synthetic operation [13][14][15][16]. From
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Published 14 Sep 2015

Pd(OAc)2-catalyzed dehydrogenative C–H activation: An expedient synthesis of uracil-annulated β-carbolinones

  • Biplab Mondal,
  • Somjit Hazra,
  • Tarun K. Panda and
  • Brindaban Roy

Beilstein J. Org. Chem. 2015, 11, 1360–1366, doi:10.3762/bjoc.11.146

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  • .11.146 Abstract An intramolecular dehydrogenative CH activation enabled an efficient synthesis of an uracil-annulated β-carbolinone ring system. The reaction is simple, efficient and high yielding (85–92%). Keywords: β-carbolinones; cyclization; dehydrogenative CH activation; Pd(OAc)2; uracil
  • dehydrogenative annulation of indole-carboxamides with alkynes etc [36]. The development of metal-catalyzed CH activation reaction has revolutionized the way a synthetic chemist now approaches a traditional C–C bond disconnection [32][33][34][35][36][37][38][39][40][41][42][43][44]. Dehydrogenative CH
  • -carbolinones via a high yielding dehydrogenative CH activation process. The key to the success of this reaction is the complementary electronic properties of the indole C3–H bond and the uracil C6–H bond. It is anticipated this efficient and atom economic approach can be emulated for the preparation of other
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Published 04 Aug 2015

Radical-mediated dehydrative preparation of cyclic imides using (NH4)2S2O8–DMSO: application to the synthesis of vernakalant

  • Dnyaneshwar N. Garad,
  • Subhash D. Tanpure and
  • Santosh B. Mhaske

Beilstein J. Org. Chem. 2015, 11, 1008–1016, doi:10.3762/bjoc.11.113

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  • persistent interest [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54]. Results and Discussion While working on the development of a palladium-catalyzed decarboxylative CH activation methodology to access the important core structure dihydroquinolone
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Published 12 Jun 2015

Chiroptical properties of 1,3-diphenylallene-anchored tetrathiafulvalene and its polymer synthesis

  • Masashi Hasegawa,
  • Junta Endo,
  • Seiya Iwata,
  • Toshiaki Shimasaki and
  • Yasuhiro Mazaki

Beilstein J. Org. Chem. 2015, 11, 972–979, doi:10.3762/bjoc.11.109

Graphical Abstract
  • carried out by direct CH activation of the TTF unit, and the chiroptical properties of the resulting polymer were also investigated. Keywords: allene; axial chirality; chiroptical properties; redox; tetrathiafulvalene; Introduction Recently, there has been a growing interest in chiral π-conjugated
  • chain scaffold (PTDPA) was also prepared using a direct CH activation of the TTF framework. The resultant chiral polymers exhibited the characteristic Cotton effect associated with the central chiral 1,3-diphenylallene moieties. The polymer also did not undergo racemization under daylight. Moreover
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Published 08 Jun 2015

Ruthenium-catalyzed C–H activation of thioxanthones

  • Danny Wagner and
  • Stefan Bräse

Beilstein J. Org. Chem. 2015, 11, 431–436, doi:10.3762/bjoc.11.49

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  • /bjoc.11.49 Abstract Thioxanthones – being readily available in one step from thiosalicylic acid and arenes – were used in ruthenium-catalyzed CH-activation reaction to produce 1-mono- or 1,8-disubstituted thioxanthones in good to excellent yields. Scope and limitation of this reaction are presented
  • . Keywords: CH activation; metal catalysis; thioxanthones; Introduction Thioxanthones (Figure 1) belong as a unique member to the large group of benzoannelated heterocycles [1]. They have found extensive use in biomedical applications (drugs and other bioactive compounds [2][3][4][5]) and material sciences
  • chemistry aiming at a high degree of substitution seems to be well explored [17][18]. This fact motivated us to extend existing methods [14][15] for the synthesis of substituted thioxanthones. We were intrigued by the fact that carbonyl-substituted arenes can undergo a smooth CH activation and alkylation
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Published 02 Apr 2015

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

  • Igor B. Krylov,
  • Vera A. Vil’ and
  • Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

Graphical Abstract
  • reactions of CH- and OH-reagents, closely related CH activation processes involving intermolecular C–O bond formation are discussed: acyloxylation reactions with ArI(O2CR)2 reagents and generation of O-reagents in situ from C-reagents (methylarenes, aldehydes, etc.). Keywords: acyloxylation; alkoxylation
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Published 20 Jan 2015

The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions

  • Alan M. Jones and
  • Craig E. Banks

Beilstein J. Org. Chem. 2014, 10, 3056–3072, doi:10.3762/bjoc.10.323

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  • to the CH activation of low reactivity intermediates. In this article, containing over 100 references, we highlight the development of the Shono-type oxidations from the original direct electrolysis methods, to the use of electroauxiliaries before arriving at indirect electrolysis methodologies. We
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Published 18 Dec 2014

Sequential decarboxylative azide–alkyne cycloaddition and dehydrogenative coupling reactions: one-pot synthesis of polycyclic fused triazoles

  • Kuppusamy Bharathimohan,
  • Thanasekaran Ponpandian,
  • A. Jafar Ahamed and
  • Nattamai Bhuvanesh

Beilstein J. Org. Chem. 2014, 10, 3031–3037, doi:10.3762/bjoc.10.321

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  • (90–105 kcal/mol) to form a new, weaker C–M bond (50–80 kcal/mol), followed by generation of a new C–C bond. Generally, transition metal-catalyzed sp2 CH activation is facilitated by directing groups [10][11][12][13] or heteroatoms in the heterocyclic compounds [14][15][16][17][18]. This methodology
  • has been applied in the synthesis of polycyclic frameworks as well as in the preparation of biologically important compounds [19][20][21][22][23]. Further development of this reaction has led to double CH activation which has been used for the construction of biaryl compounds [24][25][26][27][28][29
  • ][30][31][32][33]. The double CH activation (dehydrogenative cross coupling) reaction can be classified into two categories: intermolecular and intramolecular. There are several reports in literature describing intermolecular sp2 C–H/C–H coupling reactions [24][25][26][27][28][29][30][31][32][33
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Published 17 Dec 2014

Lewis acid-catalyzed redox-neutral amination of 2-(3-pyrroline-1-yl)benzaldehydes via intramolecular [1,5]-hydride shift/isomerization reaction

  • Chun-Huan Jiang,
  • Xiantao Lei,
  • Le Zhen,
  • Hong-Jin Du,
  • Xiaoan Wen,
  • Qing-Long Xu and
  • Hongbin Sun

Beilstein J. Org. Chem. 2014, 10, 2892–2896, doi:10.3762/bjoc.10.306

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  • : catalysis; CH activation; hydride-shift; Lewis acid; redox reaction; Introduction The direct and selective functionalization of the inactive C(sp3)–H bond constitute an economically attractive strategy for organic syntheses [1][2][3][4][5][6][7][8][9][10]. Until now, a number of transition metals can be
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Published 05 Dec 2014

Recent advances in the electrochemical construction of heterocycles

  • Robert Francke

Beilstein J. Org. Chem. 2014, 10, 2858–2873, doi:10.3762/bjoc.10.303

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  • certain functional groups [3][4]. In the last decades, research in this field has therefore been focused on the development of more efficient and selective strategies. In the current focus of heterocycle synthesis are C,H-activation with transition metal catalysts [5][6][7][8], oxidative cyclization using
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Published 03 Dec 2014

Exploration of C–H and N–H-bond functionalization towards 1-(1,2-diarylindol-3-yl)tetrahydroisoquinolines

  • Michael Ghobrial,
  • Marko D. Mihovilovic and
  • Michael Schnürch

Beilstein J. Org. Chem. 2014, 10, 2186–2199, doi:10.3762/bjoc.10.226

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  • wanted to use direct functionalization either via CH activation or cross dehydrogenative coupling for C–C-bond-forming reactions avoiding the use of two prefunctionalized building blocks. Naturally, C–N-bond formation should proceed via Buchwald–Hartwig coupling. The target molecules can be considered
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Published 15 Sep 2014

P(O)R2-directed Pd-catalyzed C–H functionalization of biaryl derivatives to synthesize chiral phosphorous ligands

  • Rong-Bin Hu,
  • Hong-Li Wang,
  • Hong-Yu Zhang,
  • Heng Zhang,
  • Yan-Na Ma and
  • Shang-dong Yang

Beilstein J. Org. Chem. 2014, 10, 2071–2076, doi:10.3762/bjoc.10.215

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  • . China 10.3762/bjoc.10.215 Abstract Chiral phosphorus ligands have been widely used in transition metal-catalyzed asymmetric reactions. Herein, we report a new synthesis approach of chiral biaryls containing a phosphorus moiety using P(O)R2-directed Pd-catalyzed CH activation; the functionalized
  • ]. Despite the progress in this area, only limited development has been accomplished through metal-catalyzed CH activation to build C–P bonds [17][18]. As an alternative, we disclosed a novel protocol of palladium-catalyzed C–H functionalization by using the P(O)R2 moiety as a new directing group to
  • -phenylboronic acid that is not applicable in these reactions. As the P(O)Ar2 group showed a better directing ability in the process of CH activation, the axial chiral P(O)(OEt)2 4a was transformed into P(O)Ar2 by reacting with an arylgrignard reagent (Scheme 2) [32]. At the same time, the racemic substrates
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Published 02 Sep 2014

Synthesis of 2-substituted tryptophans via a C3- to C2-alkyl migration

  • Michele Mari,
  • Simone Lucarini,
  • Francesca Bartoccini,
  • Giovanni Piersanti and
  • Gilberto Spadoni

Beilstein J. Org. Chem. 2014, 10, 1991–1998, doi:10.3762/bjoc.10.207

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  • ][57]. More recently, direct C2-arylation and alkylation of N-protected tryptophan methyl ester have been reported in the context of a more extensive study on CH activation reactions [58][59][60][61]. The present procedure is comparable to those described previously in terms of yield, but it is
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Published 26 Aug 2014

Synthesis of ethoxy dibenzooxaphosphorin oxides through palladium-catalyzed C(sp2)–H activation/C–O formation

  • Seohyun Shin,
  • Dongjin Kang,
  • Woo Hyung Jeon and
  • Phil Ho Lee

Beilstein J. Org. Chem. 2014, 10, 1220–1227, doi:10.3762/bjoc.10.120

Graphical Abstract
  • We report an efficient Pd-catalyzed C(sp2)–H activation/C–O bond formation for the synthesis of ethoxy dibenzooxaphosphorin oxides from 2-(aryl)arylphosphonic acid monoethyl esters under aerobic conditions. Keywords: CH activation; catalysis; cyclization; palladium; phosphorus heterocyclic compound
  • ; Introduction Unreactive C(sp2)–H and C(sp3)–H bonds are ubiquitous in organic compounds [1][2][3][4][5][6][7], so that the development of methods for the transition metal-catalyzed CH activation is one of the challenging goals in organic synthesis. Especially, the development of synthetic methods of C
  • –heteroatom bond formation via CH activation has received attention owing to the omnipresence of heterocyclic compounds in nature [8]. Recently, it has been demonstrated that the intramolecular bond formation between a heteroatom and a vicinal unreactive C–H is an efficient method for the synthesis of
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Published 23 May 2014
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