Tandem cross enyne metathesis (CEYM)–intramolecular Diels–Alder reaction (IMDAR). An easy entry to linear bicyclic scaffolds

• Javier Miró,
• María Sánchez-Roselló,
• Álvaro Sanz,
• Fernando Rabasa,
• Carlos del Pozo and
• Santos Fustero

Beilstein J. Org. Chem. 2015, 11, 1486–1493, doi:10.3762/bjoc.11.161

• 5 (method A) or acyl chlorides 6 (method B) under standard conditions (Scheme 3). Since the basic indole nitrogen in substrate 8f could interfere with the ruthenium catalyst, it was N-methylated to render compound 8g. With substrates 8 in hand, they were subjected to the optimized conditions of the

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

• reactions of secondary phosphines with several electrophiles, including alkyl halides (alkylation), alkenes (hydrophosphination) and aryl iodides (arylation). Chan et al. synthesized P-stereogenic phosphine boranes using a ruthenium catalyst. The secondary phosphine 36a underwent an enantioselective

Visible-light-induced, Ir-catalyzed reactions of N-methyl-N-((trimethylsilyl)methyl)aniline with cyclic α,β-unsaturated carbonyl compounds

• Dominik Lenhart and
• Thorsten Bach

Beilstein J. Org. Chem. 2014, 10, 890–896, doi:10.3762/bjoc.10.86

• not observed. Contrary to that, the ruthenium catalyst Ru(bpy)3Cl2 delivered a mixture of both products in a ratio of 77/23. Apart from CH2Cl2, other solvents were tested (see Supporting Information File 2), none of which led to a significant yield improvement. It was observed, however, that the

Oxidative 3,3,3-trifluoropropylation of arylaldehydes

• Akari Ikeda,
• Masaaki Omote,
• Shiho Nomura,
• Miyuu Tanaka,
• Atsushi Tarui,
• Kazuyuki Sato and
• Akira Ando

Beilstein J. Org. Chem. 2013, 9, 2417–2421, doi:10.3762/bjoc.9.279

• ][34] and Qing et al. [35] independently reported that the isomerization of a 4,4,4-trifluoromethylallyl alcohol substructure was promoted by a ruthenium catalyst to form a 3,3,3-trifluoropropylcarbonyl unit. We hypothesized that the formation of 3 would be promoted by inter- or intramolecular

Olefin metathesis in nano-sized systems

• Didier Astruc,
• Abdou K. Diallo,
• Sylvain Gatard,
• Liyuan Liang,
• Cátia Ornelas,
• Victor Martinez,
• Denise Méry and
• Jaime Ruiz

Beilstein J. Org. Chem. 2011, 7, 94–103, doi:10.3762/bjoc.7.13

• reactions can proceed in the presence of water even without surfactant, but the amount of 1st- or 2nd-generation Grubbs catalyst required then reaches 4 to 5% for good to high-yield reactions [66][67], which is of the order of 100 times more ruthenium catalyst than under our reaction conditions [63]. We

The cross-metathesis of methyl oleate with cis-2-butene-1,4-diyl diacetate and the influence of protecting groups

• Arno Behr and
• Jessica Pérez Gomes

Beilstein J. Org. Chem. 2011, 7, 1–8, doi:10.3762/bjoc.7.1

• products from 1 were obtained in lower amounts (ca. 14% of each self-metathesis product 5 and 6). From the results, it can be concluded that a catalyst loading of above 1.0 mol % of the ruthenium catalyst [Ru]-7 was necessary for efficient conversion of cis-2-butene-1,4-diyl diacetate (2). Further

• acid (7) with 2 were only achieved with the use of 3.0 mol % of the same ruthenium catalyst. Under otherwise similar reactions conditions, 75% of oleic acid was converted (Table 6, entry 2). The cross-metathesis yield amounted to 55%. In the complete absence of protecting groups, a catalyst loading of

• -metathesis of methyl oleate (1) with cis-2-butene-1,4-diyl diacetate (2) was feasible with the relatively low catalyst loading of the Schiff base ruthenium catalyst [Ru]-7 to yield two value-added and sustainable intermediates in one step. Methyl 11-acetoxyundec-9-enoate (3) and undec-2-enyl acetate (4) are

The allylic chalcogen effect in olefin metathesis

• Yuya A. Lin and
• Benjamin G. Davis

Beilstein J. Org. Chem. 2010, 6, 1219–1228, doi:10.3762/bjoc.6.140

• group on substrates (Scheme 4b). As discussed earlier, the most likely explanation for the observed rate accelerations by the allylic hydroxy groups is hydrogen-bonding. Hoveyda and co-workers recently utilized hydrogen-bonding between the allylic hydroxy group and the ruthenium catalyst for

About the activity and selectivity of less well-known metathesis catalysts during ADMET polymerizations

• Hatice Mutlu,
• Lucas Montero de Espinosa,
• Oĝuz Türünç and
• Michael A. R. Meier

Beilstein J. Org. Chem. 2010, 6, 1149–1158, doi:10.3762/bjoc.6.131

• ), 29.1 (s, CH2), 29.0 (s, CH2), 28.8 (s, CH2), 24.8 (s, CH2) ppm. MS (EI): m/z = 408 [M]+, calc. 408.3239. ADMET polymerization (P1-P26) To 1 g (2.45 mmol) of 1,3-propylene diundec-10-enoate in a tube equipped with a screw, 0.5 mol % of the corresponding ruthenium catalyst, (C1: 11.6 mg (0.0122 mmol), C2

Cross-metathesis of allylcarboranes with O-allylcyclodextrins

• Ivan Šnajdr,
• Zbyněk Janoušek,
• Jindřich Jindřich and
• Martin Kotora

Beilstein J. Org. Chem. 2010, 6, 1099–1105, doi:10.3762/bjoc.6.126

• natural and biologically active compounds [1]. One of the key aspects of this methodology, which is responsible for a high cross-metathesis selectivity, is a proper choice of a suitable ruthenium catalyst [2][3]. Efficacy of the cross-metathesis procedure has prompted also us to investigate hitherto

Synthesis of oxa-bridged derivatives from Diels–Alder bis-adducts of butadiene and 1,2,3,4-tetrahalo-5,5-dimethoxycyclopentadiene

• Faiz Ahmed Khan and
• Karuppasamy Parasuraman

Beilstein J. Org. Chem. 2010, 6, No. 64, doi:10.3762/bjoc.6.64

• 43.7 ppm and the methylene carbons at 35.9 ppm. The bis-adducts 5 and 6 were smoothly transformed to the corresponding bis-α-diketones 7 and 9 in excellent yield with a supported ruthenium catalyst (Ru-LDH) and NaIO4 as stoichiometric co-oxidant, a methodology developed in our laboratory [18][19

Asymmetric reactions in continuous flow

• Xiao Yin Mak,
• Paola Laurino and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2009, 5, No. 19, doi:10.3762/bjoc.5.19

• also been used as a heterogeneous support medium in continuous flow. A ruthenium catalyst complexed to a norephedrine-derived ligand 47 was immobilized onto modified (alkylsilyl-capped) silica and employed to catalyze a continuous asymmetric transfer hydrogenation [50] (Scheme 13). The use of

Recent progress on the total synthesis of acetogenins from Annonaceae

• Nianguang Li,
• Zhihao Shi,
• Yuping Tang,
• Jianwei Chen and
• Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

• (57), Mioskowski’s group [40] reported the first application of the RCM reaction using a ruthenium catalyst thus demonstrating the efficiency of this reaction for the construction of ACGs (Scheme 9). Both allyl alcohol 63 and vinyl-substituted epoxide 66 were synthesized via alkyne reduction yielding

Large- scale ruthenium- and enzyme- catalyzed dynamic kinetic resolution of (rac)-1-phenylethanol

• Krisztián Bogár,
• Belén Martín-Matute and
• Jan-E. Bäckvall

Beilstein J. Org. Chem. 2007, 3, No. 50, doi:10.1186/1860-5397-3-50

• -phenylethanol (2) is addressed. The immobilized lipase Candida antarctica lipase B (CALB) was employed for the resolution, which shows high enantioselectivity in the transesterification. The ruthenium catalyst used, (η 5-C5Ph5)RuCl(CO)2 1, was shown to possess very high reactivity in the "in situ" redox

Desymmetrization of 7-azabicycloalkenes by tandem olefin metathesis for the preparation of natural product scaffolds

• Wolfgang Maison,
• Marina Büchert and
• Nina Deppermann

Beilstein J. Org. Chem. 2007, 3, No. 48, doi:10.1186/1860-5397-3-48

• desymmetrization of bis-olefin 10 with the known chiral ruthenium catalyst 3.[67] This reaction gave enantioenriched 11 in good yield (Scheme 5). However, the enantioselectivity of this reaction is only moderate compared to similar reactions using molybdenum based precatalysts and different azabicycloalkene

The use of silicon- based tethers for the Pauson- Khand reaction

• Adrian P. Dobbs,
• Ian J. Miller and
• Saša Martinović

Beilstein J. Org. Chem. 2007, 3, No. 21, doi:10.1186/1860-5397-3-21

• the case of silane (6) the reaction had simply not worked, although no clear results were obtained by NMR. It has been shown that a ruthenium catalyst can cause the direct formation of silyl ethers from the silane and an alcohol. The procedure was successful for hex-1-ynyldiisopropylsilane. The