Development of chiral metal amides as highly reactive catalysts for asymmetric [3 + 2] cycloadditions

• Yasuhiro Yamashita,
• Susumu Yoshimoto,
• Mark J. Dutton and
• Shū Kobayashi

Beilstein J. Org. Chem. 2016, 12, 1447–1452, doi:10.3762/bjoc.12.140

• Schiff bases of glycine ester that proceed with low catalyst loadings (ca. 0.01 mol %). Catalytic asymmetric [3 + 2] cycloadditions of Schiff bases of α-amino esters to olefins are useful for synthesizing optically active pyrrolidine derivatives [10][11][12], and many highly stereoselective reactions

Ring-whizzing in polyene-PtL₂ complexes revisited

• Oluwakemi A. Oloba-Whenu,
• Thomas A. Albright and
• Chirine Soubra-Ghaoui

Beilstein J. Org. Chem. 2016, 12, 1410–1420, doi:10.3762/bjoc.12.135

• . We thought that by tying the ends of the olefins together via a CH2 group would force the ligand to be flat. In fact there are compounds analogous to this having O, S and Se as the linker that are in fact flat [52]. Our calculations reveal that the η2 ground state, 25, and the η4 transition state, 26

Selective bromochlorination of a homoallylic alcohol for the total synthesis of (−)-anverene

• Frederick J. Seidl and
• Noah Z. Burns

Beilstein J. Org. Chem. 2016, 12, 1361–1365, doi:10.3762/bjoc.12.129

• ; total synthesis; Introduction The directed enantioselective functionalization of olefins is an extremely powerful tool in synthesis. A preeminent example is the Sharpless asymmetric epoxidation (SAE), which has been featured in countless syntheses of enantioenriched small molecules [1][2]. While the

NeoPHOX – a structurally tunable ligand system for asymmetric catalysis

• Jaroslav Padevět,
• Marcus G. Schrems,
• Robin Scheil and
• Andreas Pfaltz

Beilstein J. Org. Chem. 2016, 12, 1185–1195, doi:10.3762/bjoc.12.114

• ligands show a much broader substrate scope in the hydrogenation of olefins, as they do not require any coordinating groups in the substrate. Although high enantioselectivities were achieved with the initially developed Ir-PHOX catalysts, the range of olefins that gave satisfactory results was limited

• . Consequently, a variety of other ligand classes derived from oxazolines or other nitrogen heterocycles were explored and eventually, several highly effective ligand systems were found that have considerably enhanced the range of functionalized and unfunctionalized olefins that can be hydrogenated with high

• . Overall, the tert-leucine-derived complex Ir-1b and complexes Ir-14-TBDMS and Ir-20-TBDMS with a bulky tert-butyldimethylsilyloxy group showed the highest reactivity, resulting in full conversion of all three olefins. On the other hand catalysts Ir-14-OH and ser-PHOX-OMe bearing a free hydroxy and a

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

• than a PhCN-containing cationic palladium(II) complex towards transmetallations with arylsilicon-containing partners and insertion of mono-cationic arylpalladium(II) species into olefins [136]. The detrimental effect of MeCN under our C–H activation conditions was further established through a series

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

• Bin Yu,
• Hui Xing,
• De-Quan Yu and
• Hong-Min Liu

Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98

• values. In addition, aliphatic β-ketoacids can also be used in the reaction, giving the corresponding alkylated 3-hydroxyoxindoles in good results under the optimized conditions. Krische and co-workers reported the first Ru-catalyzed hydrohydroxyalkylation of unactivated olefins. The direct C–C coupling

• reactions of α-olefins and styrenes with 3-hydroxy-2-oxindoles were achieved by using the ruthenium complex, giving the products as single diastereoisomers (Scheme 11) [27]. Interestingly, 1-adamantanecarboxylic acid (10 mol %) as a co-catalyst can remarkably enhance the yields from trace to >90%. A broad

• range of substituted olefins and unprotected 3-hydroxy-2-oxindoles were examined under these conditions, giving the corresponding products in excellent yields (up to 95%) and with good diastereoselectivities (up to 20:1 dr). A plausible catalytic mechanism was proposed as shown in Scheme 12. [Ru3(CO)12

A cross-metathesis approach to novel pantothenamide derivatives

• Jinming Guan,
• Matthew Hachey,
• Lekha Puri,
• Vanessa Howieson,
• Kevin J. Saliba and
• Karine Auclair

Beilstein J. Org. Chem. 2016, 12, 963–968, doi:10.3762/bjoc.12.95

• that are spectators to metathesis yet do not inactivate the catalyst. It has been shown that for optimal results (minimal homodimerization) the two olefins to undergo cross-metathesis should be of different types [20]. The two intermediates selected as possible reactants, compounds 8 and 9, were

Indenopyrans – synthesis and photoluminescence properties

• Andreea Petronela Diac,
• Ana-Maria Ţepeş,
• Albert Soran,
• Ion Grosu,
• Anamaria Terec,
• Jean Roncali and
• Elena Bogdan

Beilstein J. Org. Chem. 2016, 12, 825–834, doi:10.3762/bjoc.12.81

• halogenated lactones having the 4a,9a-fused skeleton and an ester group at position 1. The cycloaddition reaction proceeded with moderate regio- and stereoselectivity. As reported in the literature, the inverse-electron demand Diels–Alder cycloaddition of unsymmetrical olefins and oxadiazinones [33][34][35

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

• -functionalization reaction of N-(2-pyridinyl)piperazines with carbon monoxide and terminal olefins (Figure 13) [52]. Their previous work on pyridinyl group-directed Rh-catalyzed carbonylation at sp3 C–H bonds adjacent to the nitrogen atom in other alkylamines such as pyrrolidine, piperidine, and

• yields than aryl and acyl groups. Other olefins such tert-butylethylene and cyclopentene can be used as well, but the yields were significantly lower (cf. 63 and 64). The scope of the directing 2-pyridinyl group can be expanded to electron-withdrawing groups such as ester and trifluoromethyl, while

• hydroaminoalkylation for the synthesis of α-alkylated N-heterocycles from the corresponding heterocycles and alkenes [55]. Along with piperidine and azepane substrates, piperazine substrates of type 76 react smoothly with terminal olefins (78) in the presence of 10 mol % of catalyst 77 in toluene at 165 °C (Figure 14

From steroids to aqueous supramolecular chemistry: an autobiographical career review

• Bruce C. Gibb

Beilstein J. Org. Chem. 2016, 12, 684–701, doi:10.3762/bjoc.12.69

Supported bifunctional thioureas as recoverable and reusable catalysts for enantioselective nitro-Michael reactions

• José M. Andrés,
• Miriam Ceballos,
• Alicia Maestro,
• Isabel Sanz and
• Rafael Pedrosa

Beilstein J. Org. Chem. 2016, 12, 628–635, doi:10.3762/bjoc.12.61

• [12]. Cinchona-derived thioureas have been also prepared by co-polymerization of polyfunctionalized thiols with olefins [23]. Our interest in the search for novel bifunctional thioureas as organocatalysts [24][25][26][27] lead us to consider the preparation of different polymeric materials decorated

(Thio)urea-mediated synthesis of functionalized six-membered rings with multiple chiral centers

• Giorgos Koutoulogenis,
• Nikolaos Kaplaneris and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2016, 12, 462–495, doi:10.3762/bjoc.12.48

• 8-oxabicyclo[3.2.1]octane 21 framework. In this reaction, the main factor of achieving high yields or enantioselectivities, is how electron-rich or electron-poor, the dienophile is. Electron-rich olefins, like the benzyl vinyl ether and ethyl vinyl ether, reacted with success providing high yields

• two anomers. In 2012, Xie and his group envisioned the use of α,α-dicyano olefins 90, as a vinylogous Michael donor in an asymmetric Michael addition to substituted 3-nitro-2H-chromenes 91 catalyzed by bifunctional thiourea catalyst 92 (Scheme 31) [50]. When R2 is an alkyl group the reaction resulted

Aluminacyclopentanes in the synthesis of 3-substituted phospholanes and α,ω-bisphospholanes

• Vladimir A. D’yakonov,
• Alevtina L. Makhamatkhanova,
• Rina A. Agliullina,
• Leisan K. Dilmukhametova,
• Tat’yana V. Tyumkina and
• Usein M. Dzhemilev

Beilstein J. Org. Chem. 2016, 12, 406–412, doi:10.3762/bjoc.12.43

• efficient one-pot process for the synthesis of 3-substituted phospholanes and α,ω-bisphospholanes was developed. The method involves the replacement of aluminium in aluminacyclopentanes, prepared in situ by catalytic cycloalumination of α-olefins and α,ω-diolefins, by phosphorus atoms on treatment with

• ][15][16][17] would be free from the above-indicated drawbacks. Furthermore, analysis of world literature demonstrated that the data on direct transformation of aluminacarbocycles [18] to cyclic OPCs are scarce, except for paper [19] in which this approach is implemented for simple olefins. Meanwhile

• the synthesis of five-membered cyclic organophosphorus compounds, we developed a preparative process for the one-pot conversion of aluminacyclopentanes, obtained in situ by catalytic cycloalumination of olefins or diolefins with AlEt3, to phospholanes, phospholane oxides or phospholane sulfides

Art, auto-mechanics, and supramolecular chemistry. A merging of hobbies and career

• Eric V. Anslyn

Beilstein J. Org. Chem. 2016, 12, 362–376, doi:10.3762/bjoc.12.40

• challenging guests that we could envision for supramolecular chemistry to tackle are glycerides. Glycerides often differ only by numbers of methylene groups, positions of double bonds, and stereochemistry of the olefins. It seems impossibly difficult to create a synthetic receptor that could bind selectively

Simple activation by acid of latent Ru-NHC-based metathesis initiators bearing 8-quinolinolate co-ligands

• Julia Wappel,
• Roland C. Fischer,
• Luigi Cavallo,
• Christian Slugovc and
• Albert Poater

Beilstein J. Org. Chem. 2016, 12, 154–165, doi:10.3762/bjoc.12.17

• latency towards cyclic olefins. The new pre-catalysts can be triggered using HCl. Due to their extremely good solubility in apolar solvents and substrates they are useful candidates for solvent-free polymerizations. Their latency also makes them very suitable for the polymerization of strained monomers

Copper-catalyzed intermolecular oxyamination of olefins using carboxylic acids and O-benzoylhydroxylamines

• Brett N. Hemric and
• Qiu Wang

Beilstein J. Org. Chem. 2016, 12, 22–28, doi:10.3762/bjoc.12.4

• Brett N. Hemric Qiu Wang Department of Chemistry, Duke University, Durham, NC, USA 10.3762/bjoc.12.4 Abstract This paper reports a novel approach for the direct and facile synthesis of 1,2-oxyamino moieties via an intermolecular copper-catalyzed oxyamination of olefins. This strategy utilizes O

• -benzoylhydroxylamines as an electrophilic amine source and carboxylic acids as a nucleophilic oxygen source to achieve a modular difunctionalization of olefins. The reaction proceeded in a regioselective manner with moderate to good yields, exhibiting a broad scope of carboxylic acid, amine, and olefin substrates

• class of molecules is highly valued. Toward this end, intermolecular olefin oxyamination allows for direct and modular installation of both oxygen and amino groups to readily available olefins in a single step, representing a powerful and appealing approach over multistep sequences [7][8][9]. Sharpless

Effective immobilisation of a metathesis catalyst bearing an ammonium-tagged NHC ligand on various solid supports

• Krzysztof Skowerski,
• Jacek Białecki,
• Stefan J. Czarnocki,
• Karolina Żukowska and
• Karol Grela

Beilstein J. Org. Chem. 2016, 12, 5–15, doi:10.3762/bjoc.12.2

• along with the ruthenium content in crude metathesis products is summarised in Table 2. The products of RCM and ene–yne metathesis were obtained with good to excellent yields with the use of 0.1–0.5 mol % of catalyst. Functionalised olefins 19 and 21 were isolated with excellent yield after cross

New metathesis catalyst bearing chromanyl moieties at the N-heterocyclic carbene ligand

• Agnieszka Hryniewicka,
• Szymon Suchodolski,
• Agnieszka Wojtkielewicz,
• Jacek W. Morzycki and
• Stanisław Witkowski

Beilstein J. Org. Chem. 2015, 11, 2795–2804, doi:10.3762/bjoc.11.300

• route to the synthesis of functionalised olefins from simple precursors. Since the discovery of Grubbs 2nd generation catalyst (1, Figure 1) [15], Hoveyda–Grubbs 2nd generation catalyst (2, Figure 1) [16] and some successful modifications, e.g., nitro-Grela catalyst (3, Figure 1) [17] the utility of CM

• -deficient olefin (e.g., acrylates or acrylonitriles, type II or III). In these cases, full conversion and high yields can be achieved [18]. Although the problem with the CM reactions of olefins with electron-withdrawing groups, such as α,β-unsaturated ketones and esters, is partly solved [19][20], the

• -hydroxychroman and –NH2 in 6-aminochroman). Testing of the new catalyst The catalyst proved very active in model cross-metathesis reactions, especially with olefins containing electron-withdrawing groups. For example the reaction of allylbenzene and ethyl acrylate at room temperature was almost quantitative

Synthesis of bi- and bis-1,2,3-triazoles by copper-catalyzed Huisgen cycloaddition: A family of valuable products by click chemistry

• Zhan-Jiang Zheng,
• Ding Wang,
• Zheng Xu and
• Li-Wen Xu

Beilstein J. Org. Chem. 2015, 11, 2557–2576, doi:10.3762/bjoc.11.276

• olefins. Very recently, Ulven and co-workers reported the synthesis of triazole-linked phenanthroline ligands. They were obtained by the following steps: (1) 1,10-phenanthroline-2,9-dicarbaldehyde (56) was treated with the Ohira–Bestmann reagent to provide the corresponding dialkyne 57; (2) Dialkyne 57

Diversity-oriented synthesis of analogues of the novel macrocyclic peptide FR-225497 through late stage functionalization

• Jyotiprasad Mukherjee,
• Suman Sil and
• Shital Kumar Chattopadhyay

Beilstein J. Org. Chem. 2015, 11, 2487–2492, doi:10.3762/bjoc.11.270

• for the CM studies of 13 with olefins 17 and 20 (Scheme 3) for possible incorporation of additional oxygenation pattern in the 9-10 positions of the Aoda fragment in the macrocyclic target in view of the occurrence of such functionalities in compounds 2 and 3 and other related ones [22]. The known

Copper-catalyzed arylation of alkyl halides with arylaluminum reagents

• Bijay Shrestha and
• Ramesh Giri

Beilstein J. Org. Chem. 2015, 11, 2400–2407, doi:10.3762/bjoc.11.261

• on alkyl halides including highly sensitive esters (Table 2, entries, 5, 9 and 11), nitriles (Table 2, entries 6 and 7) and olefins (Table 2, entries 4, 8, 10, 13 and 15) [46]. With 10 mol % catalyst loading, the reaction can also be extended to the coupling of triarylaluminum reagents with benzyl

• electron-rich triarylaluminum reagents can be coupled with a variety of alkyl iodides and bromides containing a range of sensitive functional groups such as olefins, nitriles and esters, affording the alkylated arenes in good to excellent yields. Experimental General information. All the reactions and

Evidencing an inner-sphere mechanism for NHC-Au(I)-catalyzed carbene-transfer reactions from ethyl diazoacetate

• Manuel R. Fructos,
• Juan Urbano,
• M. Mar Díaz-Requejo and
• Pedro J. Pérez

Beilstein J. Org. Chem. 2015, 11, 2254–2260, doi:10.3762/bjoc.11.245

• carbene and the substrate. This approach would also explain the lack of formation of the olefins derived from carbene coupling with this Au(I)-based system. Conclusion The experimental results obtained from the measurement of N2 evolution in [IPrAu]+-catalyzed carbene transfer from ethyl diazoacetate have

Beyond catalyst deactivation: cross-metathesis involving olefins containing N-heteroaromatics

• Kevin Lafaye,
• Cyril Bosset,
• Lionel Nicolas,
• Amandine Guérinot and
• Janine Cossy

Beilstein J. Org. Chem. 2015, 11, 2223–2241, doi:10.3762/bjoc.11.241

• in the literature. In addition, recent mechanistic studies have focused on the rationalization of nitrogen-induced catalysts deactivation. The purpose of this mini-review is to give a brief overview of successful metathesis reactions involving olefins containing N-heteroaromatics in order to

• allow the use of primary and secondary amines in ring-closing metathesis (RCM) and cross-metathesis (CM), and one of them is the transformation of amines into carbamates, amides or sulfonamides [27][28][29]. As an alternative, metathesis reactions can be performed with olefins possessing ammonium salts

• of N-heteroaromatics containing olefins in metathesis has been less documented. In this review, we would like to give an overview of successful metatheses involving alkenes that possess N-heteroaromatics in order to delineate some guidelines. Some mechanistic insights dealing with catalyst

Olefin metathesis in air

• Lorenzo Piola,
• Fady Nahra and
• Steven P. Nolan

Beilstein J. Org. Chem. 2015, 11, 2038–2056, doi:10.3762/bjoc.11.221

• olefins. In recent years, metathesis-type reactions have emerged as universal strategies, employed in many fields of organic chemistry: from polymer chemistry [11][12][13][14][15][16][17][18] to natural product [19][20][21] and fine chemical syntheses [3][22][23][24][25]. Its importance led to the 2005

• conducted in water [31][32]. They discovered that Ru(H2O)6(tos)2 could polymerize 7-oxanorbonene 1 in water under air (Scheme 1). In 1991, Marciniec and Pietraszuck reported the catalytic activity of RuCl2(PPh3)3 in the self-metathesis of silicon-contaning olefins. The reactions were performed with 1 mol

• -workers synthesized the first well-defined ruthenium(II) complex (5, Scheme 2) bearing a carbene moiety, able to perform ring-opening metathesis polymerization (ROMP) reactions of low-strained olefins [34][35] and ring-closing metathesis (RCM) reactions of functionalized dienes [36]. In the solid state

Stereochemistry of ring-opening/cross metathesis reactions of exo- and endo-7-oxabicyclo[2.2.1]hept-5-ene-2-carbonitriles with allyl alcohol and allyl acetate

• Piotr Wałejko,
• Michał Dąbrowski,
• Lech Szczepaniak,
• Jacek W. Morzycki and
• Stanisław Witkowski

Beilstein J. Org. Chem. 2015, 11, 1893–1901, doi:10.3762/bjoc.11.204

• -oxanorbornene bearing the –CN substituent with olefins. However, Arjona and co-workers described closely related transformation of 7-oxanorbornenes (bearing carbonyl, OH and ether substituents [20]) but any detailed information about the influence of the reaction conditions on the product ratio 1-2 vs 1-3 and

• with olefins 3 and 4. Influence of the catalyst on ROCM product distribution (reaction of 1 with 3)a. Supporting Information Supporting Information File 308: MS spectra and retention indices of all compounds 5–12. Acknowledgements The authors acknowledge financial support from the Polish National