A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Ruthenium-based olefin metathesis catalysts with monodentate unsymmetrical NHC ligands

• Veronica Paradiso,
• Chiara Costabile and
• Fabia Grisi

Beilstein J. Org. Chem. 2018, 14, 3122–3149, doi:10.3762/bjoc.14.292

• strong catalytic preference of unsymmetrical N-alkyl, N’-aryl complexes to propagate as a methylidene species [30], Grubbs and co-workers developed a variety of unsymmetrical metathesis Hoveyda-type complexes (61–69, Figure 16) for applications in the ethenolysis of methyl oleate (70, Scheme 7) [31]. The

Ru complexes of Hoveyda–Grubbs type immobilized on lamellar zeolites: activity in olefin metathesis reactions

• Hynek Balcar,
• Naděžda Žilková,
• Martin Kubů,
• Michal Mazur,
• Zdeněk Bastl and
• Jiří Čejka

Beilstein J. Org. Chem. 2015, 11, 2087–2096, doi:10.3762/bjoc.11.225

• citronellene and N,N-diallyltrifluoroacetamide decreased in the order of support MCM-22 ≈ MCM-56 > SBA-15 > MCM-36; the hybrid catalyst based on SBA-15 was found the most active in self-metathesis of methyl oleate. All catalysts were reusable and exhibited low Ru leaching (<1% of Ru content). XPS analysis

• of 1,7-octadiene and (−)-β-citronellene; HGIIN+Cl− on SBA-15 (HGIIN+Cl−/SBA-15) was the most active (TON up to 16000 in RCM of citronellene). HGIIN+Cl−/SBA-15 proved its versatility in RCM, enyne metathesis, metathesis of methyl oleate, and cross-metathesis of electron deficient methyl acrylate with

• -trifluoroacetamide (DAF), and (ii) in self-metathesis and cross-metathesis of methyl oleate. Lamellar (two dimensional) zeolites represent a subgroup of zeolitic materials, in which one of the dimension of the crystals is usually limited to 2–3 nm and is around one unit cell [24][25]. Depending on the structure of

Nitro-Grela-type complexes containing iodides – robust and selective catalysts for olefin metathesis under challenging conditions

• Andrzej Tracz,
• Mateusz Matczak,
• Katarzyna Urbaniak and
• Krzysztof Skowerski

Beilstein J. Org. Chem. 2015, 11, 1823–1832, doi:10.3762/bjoc.11.198

• Hoveyda-type complexes in cross metathesis of methyl oleate with ethylene [16]. Complexes containing iodide lead to products of asymmetric OM with better enantio- and diastereoselectivity, but this came at the price of lower activity [17]. In the past few years the replacement of chloride ligands created

Intermediates in monensin biosynthesis: A late step in biosynthesis of the polyether ionophore monensin is crucial for the integrity of cation binding

• Wolfgang Hüttel,
• Jonathan B. Spencer and
• Peter F. Leadlay

Beilstein J. Org. Chem. 2014, 10, 361–368, doi:10.3762/bjoc.10.34

• derived from it, and incubated for 48 h (30 °C, 140 rpm). Production medium (soya flour (32.6 g L−1), soya oil (3.0%), methyl oleate (1.0%), glucose (20.0 g L−1), Na2SO4 (2.2 g L−1), CaCO3 (2.0 g L−1), MnCl2·4H2O (330 mg L−1), FeSO4·7H2O (110 mg L−1), Al2(SO4)3·16H2O (705 mg L−1), K2HPO4·3H2O (75 mg L−1

Hoveyda–Grubbs type metathesis catalyst immobilized on mesoporous molecular sieves MCM-41 and SBA-15

• Hynek Balcar,
• Tushar Shinde,
• Naděžda Žilková and
• Zdeněk Bastl

Beilstein J. Org. Chem. 2011, 7, 22–28, doi:10.3762/bjoc.7.4

• , respectively. The catalytic activity was tested in the RCM of 1,7-octadiene (Scheme 1, entry 1) and diethyl diallylmalonate (DEDAM) (Scheme 1, entry 2), in the metathesis of methyl oleate (Scheme 1, entry 3) and methyl 10-undecenoate (Scheme 1, entry 4), and in the ROMP of cyclooctene (Scheme 1, entry 5

• metathesis of methyl oleate and methyl 10-undecenoate. The reaction proceeded more slowly than in the case of the RCM of DEDAM (TOF at 30 min = 260 h−1 for methyl oleate and 35 h−1 for methyl 10-undecenoate, both with 3/MCM-41). The metathesis of methyl oleate reached the equilibrium after 2 h. In the case

• of methyl 10-undecenoate, the reaction rate was lower than for methyl oleate (because of probable non-productive metathesis [23]) and the final conversion was about 65% (due to the evolution of ethylene into the gas phase). There was no significant difference observed in the conversion curves for

Stereoselectivity of supported alkene metathesis catalysts: a goal and a tool to characterize active sites

• Christophe Copéret

Beilstein J. Org. Chem. 2011, 7, 13–21, doi:10.3762/bjoc.7.3

• general formula [(≡SiO)(X)M(=CHR’)(=NR)] with M = Mo or W: (E/Z)-ratio at low conversions in propene metathesis. Initial rates (TOF) and selectivity at low conversions (E/Z)0 in the metathesis of methyl oleate (0.12 M) with [(≡SiO)(t-BuCH2)Re(=CHt-Bu)(≡Ct-Bu)] (1 mol %). Stereoselectivity of Ru–NHC

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

• synthesis. An attractive, sustainable and selective (but as yet unused) method in the chemical industry is the oleochemical cross-metathesis with preferably symmetric functionalised substrates. The current study explores the cross-metathesis of methyl oleate (1) with cis-2-butene-1,4-diyl diacetate (2

• -metathesis selectivity under mild reaction conditions. These two cross-metathesis products can be potentially used as functional monomers for diverse sustainable polymers. Keywords: cross-metathesis; methyl oleate; monomer; polyester; renewable resources; Introduction In the last decade, olefin metathesis

• this article, the ruthenium catalysed cross-metathesis of methyl oleate (1) with cis-2-butene-1,4-diyl diacetate (2) (Scheme 1) will be described. This synthetic approach gives rise to another group of α,ω-difunctional substrates: The metathetical conversion studied yields methyl 11-acetoxyundec-9