Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

• Johannes Schörgenhumer,
• Maximilian Tiffner and
• Mario Waser

Beilstein J. Org. Chem. 2017, 13, 1753–1769, doi:10.3762/bjoc.13.170

• palladium-catalysed heterogeneous hydrogenation [61]. In continuation of their elegant work on generating electrophilic heteroatom-transfer reagents in situ upon adding a heteroatom nucleophile to trichloroacetonitrile (compare with Scheme 11), Ooi’s group has recently also expanded this powerful concept to

An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

• Carolina S. García,
• Paula M. Uberman and
• Sandra E. Martín

Beilstein J. Org. Chem. 2017, 13, 1717–1727, doi:10.3762/bjoc.13.166

• . Among them, cross-coupling and coupling reactions have been broadly applied for C–C and C–heteroatom bond formation [1][2][3][4][5][6]. These reactions have been proven to be powerful and attractive synthetic methods due to their high selectivity and tolerance to a wide range of functional groups on

• ). Despite that the synthesis of substituted heteroaryl derivatives is of great importance, only few examples employing heteroaryl halides in the Mizoroki–Heck reaction were reported [53]. This might be attributed to electronic aspects or poison by the heteroatom to the active Pd species [54]. However, when

Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

• Stephen Hill and
• M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 675–693, doi:10.3762/bjoc.13.67

• significantly, when compared to other reported heteroatom-doping syntheses, the fluorescence of the B-CDs was dynamically quenched by Fe3+ ions. Mechanistic studies suggested that a dynamic quenching model was prevalent at low concentrations due to interactions between Fe3+ and the CD surface, possibly

• simultaneously. For example, in 2015 Zhang et al. demonstrated that the energy intensive, hydrothermal treatment of glucose in the presence of glutathione (acting as both SPA and N/S heteroatom dopant) conducted at 180 °C for 22 h, resulted in CDs with QYs of up to 7%. The obtained CDs had blue-emissive

Transition-metal-catalyzed synthesis of phenols and aryl thiols

• Yajun Liu,
• Shasha Liu and
• Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

• other hand, the C–H hydroxylation, either with heteroatom-containing directing groups or without directing groups, has provided various methods for the synthesis of phenols. Compared with traditional methods, the transition-metal-catalyzed phenol synthesis has several advantages: broad substrate scope

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• -indanones and their heteroatom analogues 138–142 which may be further converted into biologically active compounds (Figure 4) [72]. Products 138–142 were obtained by electrocyclization of the substrates substituted by electron-withdrawing groups, such as CO2Me, P(O)(OEt)2, CN or NO2. This reaction was

Dimerization reactions of aryl selenophen-2-yl-substituted thiocarbonyl S-methanides as diradical processes: a computational study

• Michael L. McKee,
• Grzegorz Mlostoń,
• Katarzyna Urbaniak and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 410–416, doi:10.3762/bjoc.13.44

•  5). In conformer 12G, the diradical intermediate leading to product 13, where the two spins do couple, the spin density is 0.65 e−. As a model system to determine the effect of the heteroatom on the magnitude of the unpaired spin density, calculations were made for PhC(H)C4XH3, X = Se, S, O (16

• isolated from the reaction mixture. Thus, the presence of the heteroatom is of crucial importance for this new type of dimerization of aryl/hetaryl thiocarbonyl S-methanides of type 1 and this fact reflects the importance of so called ‘heavy atom effect’ [15] in the studied system. Stepwise, diradical

• interconvert readily. Potential competitive cyclization reactions of the intermediate diradical 12. a) Spin densities in the conformers 12F and 12G of diradical 12. b) Heteroatom effect on the magnitude of the spin density in the model diradical 16. Generation and typical reactions of the reactive dialkyl and

Chemical probes for competitive profiling of the quorum sensing signal synthase PqsD of Pseudomonas aeruginosa

• Michaela Prothiwa,
• Dávid Szamosvári,
• Sandra Glasmacher and
• Thomas Böttcher

Beilstein J. Org. Chem. 2016, 12, 2784–2792, doi:10.3762/bjoc.12.277

• of covalently reacting with the active site. We demonstrated the potential of our probes in a competitive labelling platform where we screened a library of synthetic HHQ and PQS analogues with heteroatom replacements and found several inhibitors of probe binding that may represent promising scaffolds

• synthetic HHQ and PQS derivatives with systematic heteroatom replacements [33]. Because the interactions of PqsD with AQs is still not entirely understood, we reasoned that HHQ or PQS analogues may be promising scaffolds for inhibitor development and we thus aimed to screen this library competitively

• the described procedures by McGlacken et al. [34] and Hradil et al. [35], respectively. We previously described the synthesis of HHQ and PQS derivatives with nitrogen in position 1 exchanged by oxygen and sulfur [33]. In our efforts to optimize the synthesis of these heteroatom derivatives we used a

A versatile route to polythiophenes with functional pendant groups using alkyne chemistry

• Xiao Huang,
• Li Yang,
• Rikard Emanuelsson,
• Jonas Bergquist,
• Maria Strømme,
• Martin Sjödin and
• Adolf Gogoll

Beilstein J. Org. Chem. 2016, 12, 2682–2688, doi:10.3762/bjoc.12.265

• conditions leading to exomethylene-EDOT [19]. Therefore, the usage of basic nucleophiles is problematic. Moreover, these heteroatom-based linkers between the polymer backbone and the pendant group usually have limited tolerance to acidic or basic conditions promoting hydrolysis, and some of them are

Et₃B-mediated and palladium-catalyzed direct allylation of β-dicarbonyl compounds with Morita–Baylis–Hillman alcohols

• Ahlem Abidi,
• Yosra Oueslati and
• Farhat Rezgui

Beilstein J. Org. Chem. 2016, 12, 2402–2409, doi:10.3762/bjoc.12.234

• ; Morita–Baylis–Hillman; palladium; triethylborane; Introduction In nucleophilic allylic substitutions, π-allylpalladium complexes are useful intermediates for the construction of carbon–carbon and carbon–heteroatom bonds in organic synthesis [1]. Usually, palladium species are used as catalysts in the

Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

• Lucie Brulíková,
• Aidan Harrison,
• Marvin J. Miller and
• Jan Hlaváč

Beilstein J. Org. Chem. 2016, 12, 1949–1980, doi:10.3762/bjoc.12.184

• biologically active compounds. It is a variant of the Diels–Alder reaction where either the diene or the dienophile contains a heteroatom. Hetero-Diels–Alder reactions between conjugated dienes and nitroso dienophiles affording 1,2-oxazines are utilized for the synthesis of many biologically active molecules

• reactions of acylnitroso compounds in [4 + 2] cycloadditions indicate several facts. The copper–oxazoline complex behaves as an excellent catalyst for the aerobic oxidation of acylhydroxamic acids. However, this system is useful only for hydroxamic acids containing a heteroatom between the aryl and carbonyl

Conjugate addition–enantioselective protonation reactions

• James P. Phelan and
• Jonathan A. Ellman

Beilstein J. Org. Chem. 2016, 12, 1203–1228, doi:10.3762/bjoc.12.116

• unsubstituted at the 2-position (R2 = H) led to lower enanantioselectivity (84:16 to 87:13 er). Products were not observed when either α-heteroatom-substituted acroleins or 3-substituted indoles were used as starting materials. When either the enantioenriched or racemic products 138 were resubmitted to the

• additions to other classes of Michael acceptors only being reported more recently. While many examples using sulfur and carbon nucleophiles have been reported, the addition of other heteroatom nucleophiles remains relatively unexplored. This approach for the synthesis of tertiary carbon stereocenters

The synthesis of functionalized bridged polycycles via C–H bond insertion

• Jiun-Le Shih,
• Po-An Chen and
• Jeremy A. May

Beilstein J. Org. Chem. 2016, 12, 985–999, doi:10.3762/bjoc.12.97

• further develop Wolff’s early work to determine selectivity patterns for transannular insertions (Scheme 7) [34][35]. His group examined the effects of heteroatom substituents such as ethers and an azide in the 3-methoxycyclohexyl substrate 34. The observed patterns largely mirrored those found in

1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

• Antonia Mielgo and
• Claudio Palomo

Beilstein J. Org. Chem. 2016, 12, 918–936, doi:10.3762/bjoc.12.90

• –C and C–heteroatom bonds [112] and have been used in many synthetic applications [113]. However one of the main limitations in the area is the lack of highly diastereo- and enantioselective protocols. In this context, particularly difficult has been to achieve high diastereoselectivity, and only a

A modular approach to neutral P,N-ligands: synthesis and coordination chemistry

• Vladislav Vasilenko,
• Torsten Roth,
• Clemens K. Blasius,
• Sebastian N. Intorp,
• Hubert Wadepohl and
• Lutz H. Gade

Beilstein J. Org. Chem. 2016, 12, 846–853, doi:10.3762/bjoc.12.83

• . In addition, the resulting ligand families should provide nitrogen and phosphorus donors with varying donor strength (amidine vs imine, phosphine vs heteroatom-bound phosphorus) and different bite angles (five- vs six-membered chelate rings). Results and Discussion Ligand synthesis We based the

Iridium/N-heterocyclic carbene-catalyzed C–H borylation of arenes by diisopropylaminoborane

• Mamoru Tobisu,
• Takuya Igarashi and
• Naoto Chatani

Beilstein J. Org. Chem. 2016, 12, 654–661, doi:10.3762/bjoc.12.65

• regioselectivity is readily predictable based on steric factors; 3) the resulting boryl group is versatile and can be converted into a variety of carbon- or heteroatom-based substituents. An iridium complex in conjunction with 4,4’-di-tert-butylbipyridine (dtbpy) developed by Ishiyama, Miyaura and Hartwig has

Copper-mediated arylation with arylboronic acids: Facile and modular synthesis of triarylmethanes

• H. Surya Prakash Rao and
• A. Veera Bhadra Rao

Beilstein J. Org. Chem. 2016, 12, 496–504, doi:10.3762/bjoc.12.49

• [1][2][3][4]. Although the group can be restricted to such molecules, many closely related derivatives that have a triarylmethane motif (like those having a heteroatom attached to the central carbon atom or the central carbon is sp2 hybridized) have been included in this class [5]. Molecules with a

Scope and limitations of the dual-gold-catalysed hydrophenoxylation of alkynes

• Adrián Gómez-Suárez,
• Yoshihiro Oonishi,
• Anthony R. Martin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2016, 12, 172–178, doi:10.3762/bjoc.12.19

• , the selectivity dropped dramatically and a 1:0.43 ratio of products was observed (3nt, Scheme 5). In order to further test our hypothesis, the polarization of the alkyne was next reduced, but the potential chelating heteroatom was retained. The hydrophenoxylation of the unsymmetrical propargylic ether

Direct estimate of the internal π-donation to the carbene centre within N-heterocyclic carbenes and related molecules

• Diego M. Andrada,
• Nicole Holzmann,
• Thomas Hamadi and
• Gernot Frenking

Beilstein J. Org. Chem. 2015, 11, 2727–2736, doi:10.3762/bjoc.11.294

• Ccarb−X bonds. The NBO data indicate that the occupation of the p(π) AO of the Ccarb atom is between 0.81 e (8, and 9) and 0.49 e (6). The p(π) occupation at the Ccarb atom is particularly large for the carbenes which have no heteroatoms bonded to it (9, and 14) or only one heteroatom as in 8. The

Recent advances in copper-catalyzed asymmetric coupling reactions

• Fengtao Zhou and
• Qian Cai

Beilstein J. Org. Chem. 2015, 11, 2600–2615, doi:10.3762/bjoc.11.280

• -catalyzed (or -mediated) asymmetric coupling reactions have received significant attention over the past few years. Especially the coupling reactions of aryl or alkyl halides with nucleophiles became a very powerful tool for the formation of C–C, C–N, C–O and other carbon–heteroatom bonds as well as for the

• construction of heteroatom-containing ring systems. This review summarizes the recent progress in copper-catalyzed asymmetric coupling reactions for the formation of C–C and carbon–heteroatom bonds. Keywords: asymmetric; carbon–heteroatom bond; copper; coupling; Introduction Copper-mediated coupling

• reactions to be carried out under much milder conditions. In the meantime these reactions have become one of the most classic, efficient and powerful methods for the formation of C–C, C–N, C–O and other carbon–heteroatom bonds. Extensive applications have been developed in both academia and industry [6][7

Copper-catalyzed asymmetric conjugate addition of organometallic reagents to extended Michael acceptors

• Thibault E. Schmid,
• Sammy Drissi-Amraoui,
• Christophe Crévisy,
• Olivier Baslé and
• Marc Mauduit

Beilstein J. Org. Chem. 2015, 11, 2418–2434, doi:10.3762/bjoc.11.263

• ; sequential addition; Introduction Amongst the variety of synthetic methods available for the formation of C–C or C–heteroatom bonds, the asymmetric conjugate addition (ACA) of nucleophiles to electron-deficient alkenes is one of the most relevant and versatile for the synthesis of complex chiral molecules

Co-solvation effect on the binding mode of the α-mangostin/β-cyclodextrin inclusion complex

• Chompoonut Rungnim,
• Sarunya Phunpee,
• Manaschai Kunaseth,
• Supawadee Namuangruk,
• Kanin Rungsardthong,
• Thanyada Rungrotmongkol and
• Uracha Ruktanonchai

Beilstein J. Org. Chem. 2015, 11, 2306–2317, doi:10.3762/bjoc.11.251

• around the α-MGS in the formed inclusion complexes. The gij(r) was calculated as a function of the ethanol or water oxygen atom j within a spherical radius of r from the α-MGS heteroatom (oxygen atom i). The RDF results of ethanol and water co-solvation are shown in the left and right columns of Figure 6

Molecular-oxygen-promoted Cu-catalyzed oxidative direct amidation of nonactivated carboxylic acids with azoles

• Wen Ding,
• Shaoyu Mai and
• Qiuling Song

Beilstein J. Org. Chem. 2015, 11, 2158–2165, doi:10.3762/bjoc.11.233

• [25][26]. Currently, copper-catalyzed, aerobic, oxidative transformations with dioxygen as the sole oxidant have emerged as a useful and powerful strategy to construct carbon–carbon and carbon–heteroatom bonds [27][28][29]. It is known that Cu(II) superoxide species are usually reported to be formed

Investigation of the role of stereoelectronic effects in the conformation of piperidones by NMR spectroscopy and X-ray diffraction

• Cesar Garcias-Morales,
• David Ortegón-Reyna and
• Armando Ariza-Castolo

Beilstein J. Org. Chem. 2015, 11, 1973–1984, doi:10.3762/bjoc.11.213

• hyperconjugation, which is related to the anomeric effect (effect where a heteroatomic substituent adjacent to a heteroatom within a cyclohexane ring prefers the axial orientation instead of the equatorial) [6][7][8][9][10][11][12]. Moreover, stereoelectronic effects have been related to the stabilization of

• heteroatom, this is known as homoanomeric effect, which is a type of homohyperconjugation [28][29][30][31][32][33][34][35][36]. The homoanomeric effect can be observed in two cases: the first-one through a W-arrangement, where the lone-pair electrons (LPEs) of O, N, and S, on the pseudo equatorial position

New aryloxybenzylidene ruthenium chelates – synthesis, reactivity and catalytic performance in ROMP

• Patrycja Żak,
• Szymon Rogalski,
• Mariusz Majchrzak,
• Maciej Kubicki and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2015, 11, 1910–1916, doi:10.3762/bjoc.11.206

• . Coordination motif of latent catalyst of olefin metathesis in which alkylidene ligand is bound to the heteroatom X, acting as an anionic ligand. Known latent catalysts of olefin metathesis in which alkylidene ligands are bound to a heteroatom, acting as an anionic ligand. Selected, known aryloxybenzylidene

A comprehensive study of olefin metathesis catalyzed by Ru-based catalysts

• Albert Poater and
• Luigi Cavallo

Beilstein J. Org. Chem. 2015, 11, 1767–1780, doi:10.3762/bjoc.11.192

• field for the synthesis of C–C double bonds [7][8][9]. After the discovery of well-defined Ru-based (pre)catalysts, such as (PCy3)2Cl2Ru=CHPh [10], first by Grubbs and co-workers the range of these catalysts was broadened because of their tolerancy towards heteroatom ligands and the possibility to work

• Table 2), is due to the coordination of the O atom of the substrate in 14–19. In other words, with a heteroatom containing substrate the heteroatom can coordinate to the Ru center, as in the Hoveyda-type precatalysts [6], maybe stabilizing the active species, see Figure 3a. In any case, coordination of

• overall uphill path. Coordination of the terminal C=C double bond with respect to coordination of the O heteroatom is disfavored by 4.5 kcal/mol in 14 and favored by 1.8 kcal/mol in 16, respectively. The transition states are 20.2 and 19.9 kcal/mol higher in energy with respect to the 14e species, and the