Relay cross metathesis reactions of vinylphosphonates

• Raj K. Malla,
• Jeremy N. Ridenour and
• Christopher D. Spilling

Beilstein J. Org. Chem. 2014, 10, 1933–1941, doi:10.3762/bjoc.10.201

• phosphorus; relay; vinyl phosphonate; Introduction Over the last two decades, we have developed reactions for the formation of chiral non-racemic γ-substituted vinylphosphonates [1][2][3][4][5][6][7][8][9]. In particular, carbonate derivatives 1 (phosphono allylic carbonates) of allylic hydroxy phosphonates

• chromatography resulted in some loss of material leading to an isolated yield of 45%. In addition, the 31P NMR spectrum of the crude reaction mixture indicated the formation of a new phosphorus-containing product with a signal at 43 ppm, consistent with formation of the oxaphosphole 22 [25]. An impure sample of

• of vinylphosphonate 21a with styrenes. The dimeric product 27 was not observed during the cross metathesis of the vinylphosphonate 21a with methyl acrylate. Diallyl vinylphosphonates (28) are reported to undergo ring closing metathesis to give either 7-membered (29) or 5-membered (30) phosphorus

Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

• Thilo Focken and
• Stephen Hanessian

Beilstein J. Org. Chem. 2014, 10, 1848–1877, doi:10.3762/bjoc.10.195

• enolization. Thus, treatment of Δ5-cholestenone with 24a yielded the unconjugated olefin 27a in addition to recovered unreacted enone, whereas phosphorus ylides would form Δ4-cholestenone via enolization and double bond conjugation [20]. Other monocyclic phosphonamides with application in olefination

• phosphorus center, whereas cis confers to a R-configuration. Degradation of the adducts by ozonolysis yielded oxocycloalkane-3-carboxaldehydes 43, which are useful synthetic intermediates. Diastereomer cis-40b however gave only poor diastereofacial selection, providing the corresponding 1,4-addition adducts

• dichlorides can be obtained either from chlorination of phosphonic acids [65][66] or from treatment of an allyl chloride such as 61 with phosphorus trichloride followed by hydrolysis to give 62 [15][67]. Reactions of unsymmetrical amines or aminoalcohols such as ephedrine with phosphonic acid dichlorides

The chemoenzymatic synthesis of clofarabine and related 2′-deoxyfluoroarabinosyl nucleosides: the electronic and stereochemical factors determining substrate recognition by E. coli nucleoside phosphorylases

• Ilja V. Fateev,
• Konstantin V. Antonov,
• Irina D. Konstantinova,
• Tatyana I. Muravyova,
• Frank Seela,
• Roman S. Esipov,
• Anatoly I. Miroshnikov and
• Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2014, 10, 1657–1669, doi:10.3762/bjoc.10.173

• atoms (C-5OH···FC-2 1.98 Å). The other structure (C-3-exo conformer; ET = −732310.1 kcal/mol) does not contain the intramolecular hydrogen bonds. The torsion angles of the vicinal hydrogen atoms H-1/H-2 and H-2/H-3, the hydrogen–fluorine (H-1/F and H-3/F) and hydrogen–phosphorus (H-1/P), and the carbon

• –fluorine (C-4/F) and carbon–phosphorus (C-2/P) atoms are in satisfactory agreement with the experimental coupling constants. On the other hand, the vicinal torsion H-3/H-4 angles (79° and 91°) are not in accordance with the relevant coupling constant (5.40 Hz). However, the H-3/H-4 torsion angle (162°) of

Synthesis of new, highly luminescent bis(2,2’-bithiophen-5-yl) substituted 1,3,4-oxadiazole, 1,3,4-thiadiazole and 1,2,4-triazole

• Anastasia S. Kostyuchenko,
• Vyacheslav L.Yurpalov,
• Aleksandra Kurowska,
• Wojciech Domagala,
• Adam Pron and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2014, 10, 1596–1602, doi:10.3762/bjoc.10.165

• with phosphorus oxychloride, in 78 and 83% yields, respectively. The reaction of 11 with a Lawesson’s reagent led to the formation of 2,5-bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-tiadiazole (15, 70% yield) (Scheme 4). To the contrary, 3,5-bis(3-decyl-2,2'-bithiophen-5-yl)-4-phenyl-4H-1,2,4-triazole (18

• -N-phenyl-2,2'-bithiophene-5-carboximidoyl chloride (17) by the reaction with phosphorus pentachloride, and then, without additional purification, used at once in the reaction with acyl hydrazide 10. As a result, 3,5-bis(3-decyl-2,2'-bithiophen-5-yl)-4-phenyl-4H-1,2,4-triazole (18) was obtained in 62

Rational design of cyclopropane-based chiral PHOX ligands for intermolecular asymmetric Heck reaction

• Marina Rubina,
• William M. Sherrill,
• Alexey Yu. Barkov and
• Michael Rubin

Beilstein J. Org. Chem. 2014, 10, 1536–1548, doi:10.3762/bjoc.10.158

• , possessing a diphenylphosphanyl group and ligand L3 derived from tert-leucinol (Figure 3). Not surprisingly, installation of the less hindered phosphorus moiety in L2 negatively affected the asymmetric induction: the corresponding product 3a was obtained in only 78–79% ee (Table 2, entries 3 and 4). However

• assessed the possibility of conformational equilibrium for the six-membered arylpalladium species bearing L1 (Scheme 4). The non-planar six-membered palladacycle [66][67][68][69] can potentially adopt one of two conformations: I1, in which the syn-tert-butyl substituent at phosphorus assumes a pseudo

• thermodynamically disfavored compared to I1. This hypothesis was also supported by a single crystal X-ray analysis of (L1)PdCl2 complex (Figure 4). The resolved crystal structure clearly shows that the syn-(C14) and anti-substituent (C18) at phosphorus adopt a pseudo-equatorial and a pseudo-axial position

Synthesis, characterization and DNA interaction studies of new triptycene derivatives

• Sourav Chakraborty,
• Snehasish Mondal,
• Rina Kumari,
• Sourav Bhowmick,
• Prolay Das and
• Neeladri Das

Beilstein J. Org. Chem. 2014, 10, 1290–1298, doi:10.3762/bjoc.10.130

• these compounds is attributed to the interaction of the electronic states of the compounds with significant contribution from the phosphorus atom with the phosphate backbone of DNA from just sitting on the grooves. The cleavage of supercoiled plasmid by the TPAs (5 and 6) indicates possible formation of

Synthesis of 1-[bis(trifluoromethyl)phosphine]-1’-oxazolinylferrocene ligands and their application in regio- and enantioselective Pd-catalyzed allylic alkylation of monosubstituted allyl substrates

• Zeng-Wei Lai,
• Rong-Fei Yang,
• Ke-Yin Ye,
• Hongbin Sun and
• Shu-Li You

Beilstein J. Org. Chem. 2014, 10, 1261–1266, doi:10.3762/bjoc.10.126

• an elegant synthesis of bis(perfluoroalkyl)phosphine-oxazoline ligands where small but strongly electron-withdrawing substituents were introduced at the phosphorus [34]. 1,2-Ferrocene based P,N-ligands were synthesized and gave excellent regio- and enantioselectivities in the Pd-catalyzed allylic

• the R group has the ability to stabilize the carbocation, the electronic factor would favor the formation of the branched product (path b). The phosphorus atom has a stronger trans effect comparing with the oxazoline nitrogen, indicating that the carbon trans to phosphorus atom bears more

• electropositivity [46]. This fact may be responsible for the preferred placement of the substituted allylic carbon in the trans position to the phosphorus atom to better stabilize the electropositivity of the carbon. When the nucleophile attacks the more electropositive substituted allylic carbon terminus, a

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

• 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: C–H activation; catalysis; cyclization; palladium; phosphorus heterocyclic compound

Atherton–Todd reaction: mechanism, scope and applications

• Stéphanie S. Le Corre,
• Mathieu Berchel,
• Hélène Couthon-Gourvès,
• Jean-Pierre Haelters and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117

• design of phosphorus-based amphiphilic compounds. 2. Mechanism of the Atherton–Todd reaction In their initial publication, Atherton and Todd have suggested two possible mechanisms to explain the formation of phosphoramidate [1]. The first one (Scheme 2-i) was based on a two-step sequence with the

• by the existence of some similitude with the reactivity of carbon tetrachloride reported in literature (e.g., the synthesis of arylcarboxylate according to a Reimer–Tiemann reaction [3][4]) and because the second step (i.e., the nucleophilic substitution on the electrophilic phosphorus) shares some

• in favor of the addition of the nucleophilic amine on chlorophosphorinane as intermediate. All the studies reported above shed some light on the mechanism of the AT reaction. None of these studies, however, focused on the chirality at the phosphorus atom. The first investigation of the

Novel indolin-2-one-substituted methanofullerenes bearing long n-alkyl chains: synthesis and application in bulk-heterojunction solar cells

• Irina P. Romanova,
• Andrei V. Bogdanov,
• Inessa A. Izdelieva,
• Vasily A. Trukhanov,
• Gulnara R. Shaikhutdinova,
• Dmitry G. Yakhvarov,
• Shamil K. Latypov,
• Vladimir F. Mironov,
• Vladimir A. Dyakov,
• Ilya V. Golovnin,
• Dmitry Yu. Paraschuk and
• Oleg G. Sinyashin

Beilstein J. Org. Chem. 2014, 10, 1121–1128, doi:10.3762/bjoc.10.111

• crystalline domains. Moreover, the more soluble AIMs do not show a better miscibility with the P3HT crystalline phase. Keywords: bulk heterojunction; fullerenes; isatin; phosphorus; photovoltaics; Introduction Organic photovoltaics are a rapidly growing field of research due to its potential for production

Preparation of phosphines through C–P bond formation

• Iris Wauters,
• Wouter Debrouwer and
• Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

• ; enantioselectivity; hydrophosphination; organophosphorus chemistry; phosphines; phosphine-boranes; substitution reactions; trivalent phosphorus; Introduction Phosphines are an important class of organophosphorus compounds. They are often used as ligands in metal complex catalysis and they have become a popular

• reagent for organocatalysis [1]. The methods most widely used for the synthesis of phosphines include the reaction of organometallic compounds with halophosphines, the reaction of metal phosphides with alkyl halides, the reduction of other phosphorus compounds and the hydrophosphination [2]. Research in

• asymmetric synthesis [5][6]. Only a minor part of the chiral phosphines are chiral at the phosphorus atom (P-stereogenic) [7][8][9]. A major drawback of phosphines is their highly oxidizable nature. They are easily converted to the corresponding phosphine oxide which makes the isolation difficult. To prevent

Theoretical studies on the intramolecular cyclization of 2,4,6-t-Bu₃C₆H₂P=C: and effects of conjugation between the P=C and aromatic moieties

• Masaaki Yoshifuji and
• Shigekazu Ito

Beilstein J. Org. Chem. 2014, 10, 1032–1036, doi:10.3762/bjoc.10.103

• the phosphorus atom play an important role in the chemistry of low-coordinate phosphorus compounds and the supermesityl (Mes* = 2,4,6-tri-tert-butylphenyl) group was successfully applied to stabilize and characterize a diphosphene (Mes*P=PMes*) for the first time [1]. The effect of the Mes* group on

• the stabilization of various kinds of unusual phosphorus compounds has been clarified so far [2][3][4]. Phosphanylidenecarbene [RP=C:], a heavier congener of alkylidenecarbene (phosphaisonitrile) has been an intriguing reaction intermediate containing a low-coordinated phosphorus atom, and afforded a

• number of unique organophosphorus compounds [5][6]. The phosphorus version of Fritsch–Buttenberg–Wiechell (FBW) reaction [7][8][9][10] of Mes*P=C(X)Li (X = halogen, Mes* = 2,4,6-t-Bu3C6H2) affording an air-stable phosphaalkyne Mes*C≡P is a typical example for understanding the chemistry of a

Allenylphosphine oxides as simple scaffolds for phosphinoylindoles and phosphinoylisocoumarins

• G. Gangadhararao,
• Ramesh Kotikalapudi,
• M. Nagarjuna Reddy and
• K. C. Kumara Swamy

Beilstein J. Org. Chem. 2014, 10, 996–1005, doi:10.3762/bjoc.10.99

• . Interestingly, in the presence of wet trifluoroacetic acid, in addition to phosphinoylisocoumarins, phosphorus-free isocoumarins were also obtained. Key products were characterized by single crystal X-ray crystallography. Keywords: allenes; indoles; isocoumarins; organophosphorus; phosphinoyl-heterocycles

• ][18][19] and as reagents in organic synthesis [20]. In our previous reports, we described the utility of phosphorus-based allenes in various cyclization reactions involving heteroatoms that could lead to phosphono/phosphinoyl hetero-/carbocycles [21][22][23][24][25][26][27][28][29][30]. The reported

• formed (Scheme 3). The presence of a doublet for PCH carbon at δ 48.3 with a 1J(P–C) value of 62.0 Hz reveals that the phosphorus moiety is attached to an sp3-hybridized carbon. On the other hand, in the reaction using the =CHMe allene 3m, two isomers in which the N–H proton moves to either the α-carbon

Addition of H-phosphonates to quinine-derived carbonyl compounds. An unexpected C9 phosphonate–phosphate rearrangement and tandem intramolecular piperidine elimination

• Łukasz Górecki,
• Artur Mucha and
• Paweł Kafarski

Beilstein J. Org. Chem. 2014, 10, 883–889, doi:10.3762/bjoc.10.85

• skeleton and a phosphorus atom. For the C9 ketones a phosphonate–phosphate rearrangement, associated with a tandem elimination of the piperidine fragment, was evidenced. Keywords: carbonyl derivatives; dialkyl phosphite addition; organophosporus; phosphonate–phosphate rearrangement; quinine oxidation

• , phosphorus compounds chemistry, particularity that avoiding an expansion of the core carbon skeleton [10][11][12][13], is poorly recognized and mainly involves esterification of different phosphorus acids with the O-9-hydroxy group [14][15][16][17][18][19][20][21]. These phosphorus esters were consecutively

• applied in organo- and metal-assisted catalysis [14][17][18][19][20] and NMR-monitored enantiodiscrimination [21]. According to our knowledge no example of formation of a direct C–P linkage between the quinine backbone and a phosphorus atom has been reported in the literature. Stimulated by this challenge

Synthesis of fluorescent (benzyloxycarbonylamino)(aryl)methylphosphonates

• Michał Górny vel Górniak,
• Anna Czernicka,
• Piotr Młynarz,
• Waldemar Balcerzak and
• Paweł Kafarski

Beilstein J. Org. Chem. 2014, 10, 741–745, doi:10.3762/bjoc.10.68

• obtained by using the classical three-component amidoalkylation procedure described by Oleksyszyn et al. (Scheme 1) [14]. First, appropriate triaryl phosphites have to be synthesized. They were obtained by refluxing stoichiometric quantities of phosphorus trichloride with the appropriate phenol (molar

• ratio 1:3) in acetonitrile [16][17]. The desired phosphites deposited from acetonitrile as solids or oils and did not require further purification. Corresponding reactions carried out in different solvents (toluene, benzene or diethyl ether in the presence of butyllithium in hexane) or with phosphorus

• report on its application to synthesize phosphorus esters. After dissolving the substrates the catalyst was added to the reaction mixture and it was carried under reflux for 6 h. Optimization of the reaction conditions revealed that a mixture of dioxane and water (out of: dioxane, acetonitrile

Phosphinate-containing heterocycles: A mini-review

• Olivier Berger and
• Jean-Luc Montchamp

Beilstein J. Org. Chem. 2014, 10, 732–740, doi:10.3762/bjoc.10.67

• rare. The growing availability of synthetic methods will undoubtedly change this situation in the near future. Keywords: amino acid; heterocyle; organophosphorus; phosphinic; phosphorus; Introduction The preparation of P-heterocycles has been the subject of many studies over the years, and the field

A novel family of (1-aminoalkyl)(trifluoromethyl)- and -(difluoromethyl)phosphinic acids – analogues of α-amino acids

• Natalia V. Pavlenko,
• Tatiana I. Oos,
• Yurii L. Yagupolskii,
• Igor I. Gerus,
• Uwe Doeller and
• Lothar Willms

Beilstein J. Org. Chem. 2014, 10, 722–731, doi:10.3762/bjoc.10.66

• , bearing side chain C–F linkages are well documented in a review [10]. The isolation of phosphinothricin, a naturally occurring phosphorus analogue of glutamic acid and the discovery of its antibiotic, fungicidal and herbicidal properties [11] has led to an increased activity in the study of

• methylphosphinic acid analogues of the protein amino acids [12] and those of glycine [13], alanine [14], valine [14], leucine [15], proline [16], aspartic [17] and glutamic [11] acids and GABA [18] have been described. But almost nothing is known about phosphorus isosters of aminocarboxylic acids bearing a

• the GABAB receptor [18]. In light of the above and in connection with our interest in the chemistry of fluorinated compounds of phosphorus we report here the preparation of a series of novel (1-aminoalkyl)phosphinic acids bearing CF3 or CHF2 groups at phosphorus. Results and Discussion Research

Zirconoarylation of alkynes through p-chloranil-promoted reductive elimination of arylzirconates

• Xiaoyu Yan,
• Chao Chen and
• Chanjuan Xi

Beilstein J. Org. Chem. 2014, 10, 528–534, doi:10.3762/bjoc.10.48

• Xiaoyu Yan Chao Chen Chanjuan Xi Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China 10.3762

Concise, stereodivergent and highly stereoselective synthesis of cis- and trans-2-substituted 3-hydroxypiperidines – development of a phosphite-driven cyclodehydration

• Peter H. Huy,
• Julia C. Westphal and
• Ari M. P. Koskinen

Beilstein J. Org. Chem. 2014, 10, 369–383, doi:10.3762/bjoc.10.35

• –99%) (Table 2, entries 2, 11, 13 and 16). For both cyclodehydration methods (with PPh3 and P(OEt)3) neat iodine was simply added to a solution of the amino alcohols 9a–d, the phosphorus reagent and Et3N in the reaction solvent at the indicated temperature (−40 °C and −78 °C, respectively) and stirred

New hydrogen-bonding organocatalysts: Chiral cyclophosphazanes and phosphorus amides as catalysts for asymmetric Michael additions

• Helge Klare,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2014, 10, 224–236, doi:10.3762/bjoc.10.18

• catalysts based on rigid cis-PV-cyclodiphosphazane amides of N1,N1-dimethylcyclohexane-1,2-diamine have been developed. Employed in the asymmetric Michael addition of 2-hydroxynaphthoquinone to β-nitrostyrene, the open-chain 9-epi-aminochinchona-based phosphorus amides show a high catalytic activity with

• defined geometry. Introducing a new motif, Shea et al. have synthesized achiral tridentate (thio)phosphorus triamides and assessed their catalytic activity relative to the established (m-(CF3)2-Ph)2thiourea [18]. In the Friedel–Crafts reaction of N-methylindole with β-nitrostyrene and the Baylis–Hillman

• characteristics and the increased steric bulk of “3-D”-PV compared to “2-D” urea or squaramides make phosphorus triamides excellent candidates for asymmetric (HB) organocatalysts. However, the tetrahedral structure of PV-amides also enables a higher degree of conformational freedom combined with a less rigid

Recent applications of the divinylcyclopropane–cycloheptadiene rearrangement in organic synthesis

• Sebastian Krüger and
• Tanja Gaich

Beilstein J. Org. Chem. 2014, 10, 163–193, doi:10.3762/bjoc.10.14

• corresponding cis-divinylcyclopropane (9). Calculations have been carried out for cis-divinylheterocyclopropanes including nitrogen, oxygen, sulfur and phosphorus substitution [22], as well as cis-1,2-cyclobutanes [19][23]. Earlier calculations have been carried out for mono-heteroatom substitution in the vinyl

Charge-transfer interaction mediated organogels from 18β-glycyrrhetinic acid appended pyrene

• Jun Hu,
• Jindan Wu,
• Qian Wang and
• Yong Ju

Beilstein J. Org. Chem. 2013, 9, 2877–2885, doi:10.3762/bjoc.9.324

• Jun Hu Jindan Wu Qian Wang Yong Ju Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China, Department of Chemistry and Biochemistry, University of South Carolina, Columbia, 29208, USA

Total synthesis of the endogenous inflammation resolving lipid resolvin D2 using a common lynchpin

• John Li,
• May May Leong,
• Alastair Stewart and
• Mark A. Rizzacasa

Beilstein J. Org. Chem. 2013, 9, 2762–2766, doi:10.3762/bjoc.9.310

• using the common linchpin phosphorus ylide derived from phosphonium salt 6 [21][22] and each of the homochiral aldehydes 5 and 7 [9]. Synthesis of vinyl iodide 4 The synthesis of fragment 4 began with the production of the aldehyde 7 as shown in Scheme 2. A Wittig reaction between hemiacetal 8 [23] and

Advancements in the mechanistic understanding of the copper-catalyzed azide–alkyne cycloaddition

• Regina Berg and
• Bernd F. Straub

Beilstein J. Org. Chem. 2013, 9, 2715–2750, doi:10.3762/bjoc.9.308

• -phenanthroline derivatives is present in the reaction mixture [80]. Although the structural characteristics of the corresponding copper complexes remain elusive, these ligands are frequently applied in CuAAC reactions, especially in macromolecular chemistry [15]. Apart from N-donor ligands, the use of phosphorus

• CuAAC catalysis. With this ligand (30 mol %) and copper(I) bromide (5 mol %) the reaction of benzyl azide with phenylacetylene is completed within 10 minutes in aqueous solution at room temperature under aerobic conditions [118]. Phosphorus ligands in combination with copper(I) salts have been reported

• ). As copper(I) thiolate complexes show a high tendency to form aggregates [133][134][135][136], speciation and nuclearity of the catalytically active species remain unknown. Copper(I) complexes with phosphorus ligands, for example the commercially available air-stable salts [CuBr(PPh3)3] and {CuI[P(OEt

An efficient method for the construction of polysubstituted 4-pyridones via self-condensation of β-keto amides mediated by P₂O₅ and catalyzed by zinc bromide

• Liquan Tan,
• Peng Zhou,
• Cui Chen and
• Weibing Liu

Beilstein J. Org. Chem. 2013, 9, 2681–2687, doi:10.3762/bjoc.9.304

• Liquan Tan Peng Zhou Cui Chen Weibing Liu School of Chemistry and Life Science, Guangdong University of Petrochemical Technology, 2 Guangdu Road, Maoming 525000, China 10.3762/bjoc.9.304 Abstract A self-condensation cyclization reaction mediated by phosphorus pentoxide (P2O5) and catalyzed by

• -aryl β-keto amides as the substrates in this protocol, 4-pyridones are resulted, however, when using N-aliphatic-substituted β-keto amides as the partners of N-aryl β-keto amides under the same conditions, 2-pyridones are afforded. Keywords: β-keto amide; phosphorus pentoxide; 2-pyridones; 4-pyridones

• Ovenden used tosic acid to catalyze this transformation [20]. In this article, we report an improved efficient method for the construction of polysubstituted 4-pyridones and 2-pyridones via phosphorus pentoxide-mediated self-condensation of β-ketobutylanilides catalyzed by zinc bromide (Scheme 2). It is