Aqueous olefin metathesis: recent developments and applications

• Valerio Sabatino and
• Thomas R. Ward

Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39

• diallylmalonate 31 in DCM (Scheme 11). Upon reaction completion, the catalyst is extracted from the organic reaction mixture with D2O and (re)-used for the isomerization of cis-butenediol Z-58 in water. Recently the removal of a water-soluble catalyst from reaction mixtures was also achieved with catalyst 12

• % conversion of substrate 21 and quantitative conversion of substrate 64. The water-soluble catalyst 9 was compared to the hybrid catalysts, displaying a higher TON in the RCM of 21 (Table 9, entry 4). Interestingly, the activity of catalyst 9 is inhibited in the presence of NB4exp (Table 9, entries 5 and 10

• phosphine-based catalysts bearing quaternary ammonium tags 1 and 2. Synthesis of water-soluble catalysts 3 and 4 bearing quaternary ammonium tags. In situ formation of catalyst 5 bearing a quaternary ammonium group. Catalyst recycling of an ammonium-bearing catalyst. Removal of the water-soluble catalyst 12

Reusable and highly enantioselective water-soluble Ru(II)-Amm-Pheox catalyst for intramolecular cyclopropanation of diazo compounds

• Hamada S. A. Mandour,
• Yoko Nakagawa,
• Masaya Tone,
• Hayato Inoue,
• Nansalmaa Otog,
• Ikuhide Fujisawa,
• Soda Chanthamath and
• Seiji Iwasa

Beilstein J. Org. Chem. 2019, 15, 357–363, doi:10.3762/bjoc.15.31

• crucial for the intramolecular cyclopropanation reaction in a water/ether biphasic medium. The water-soluble catalyst could be reused at least six times with little loss in yield and enantioselectivity. Keywords: asymmetric synthesis; carbene transfer; cyclopropanation; diazoester; intramolecular

• diazoamide; Ru(II)-Pheox; water-soluble catalyst; Weinreb amide; Introduction Water-soluble transition metal complexes have been attracting increasing interest for catalytic applications because of their many advantages such as simple product separation, low cost, safety, and environmentally friendly

• . During the reaction process, no other stereoisomers were obtained. Next, the reusability of water-soluble catalyst cat. 2 was examined. After separation of the ether layer, the aqueous phase was extracted with diethyl ether several times until no product remained. A new solution of trans-allylic diazo

An efficient Pd–NHC catalyst system in situ generated from Na₂PdCl₄ and PEG-functionalized imidazolium salts for Mizoroki–Heck reactions in water

• Nan Sun,
• Meng Chen,
• Liqun Jin,
• Wei Zhao,
• Baoxiang Hu,
• Zhenlu Shen and
• Xinquan Hu

Beilstein J. Org. Chem. 2017, 13, 1735–1744, doi:10.3762/bjoc.13.168

• functionalization of the N atom of the NHC ring allows for the possible incorporation of water soluble moieties, thus providing more opportunities for water soluble catalyst design [37][38][39]. Since the pioneering report of a sulfonate-functionalized NHC ligand by Shaughnessy [40], a number of water-soluble NHC

Hexacoordinate Ru-based olefin metathesis catalysts with pH-responsive N-heterocyclic carbene (NHC) and N-donor ligands for ROMP reactions in non-aqueous, aqueous and emulsion conditions

• Shawna L. Balof,
• K. Owen Nix,
• Matthew S. Olliff,
• Sarah E. Roessler,
• Arpita Saha,
• Kevin B. Müller,
• Ulrich Behrens,
• Edward J. Valente and
• Hans-Jörg Schanz

Beilstein J. Org. Chem. 2015, 11, 1960–1972, doi:10.3762/bjoc.11.212

• capacity make organic transformations using hydrophilic catalyst in aqueous media very attractive [14][15][16][17][18]. These benefits, coupled with potential applications in biological media [19], have led to the development of various water-soluble catalyst designs [20][21]. Such catalysts contain

• develop water-soluble catalyst systems which can perform the task with high activity, substrate range and sufficient hydrolytic stability to access a variety of novel ROMP latexes. We now wish to report the synthesis of two new pH-responsive, Ru-based olefin metathesis catalysts, their ROMP and ring

Effective ascorbate-free and photolatent click reactions in water using a photoreducible copper(II)-ethylenediamine precatalyst

• Redouane Beniazza,
• Natalia Bayo,
• Florian Molton,
• Carole Duboc,
• Stéphane Massip,
• Nathan McClenaghan,
• Dominique Lastécouères and
• Jean-Marc Vincent

Beilstein J. Org. Chem. 2015, 11, 1950–1959, doi:10.3762/bjoc.11.211

• . A major application of the CuAAC concerns bioconjugation reactions, i.e., the covalent modification of biomolecules [6]. Such reactions typically imply water-soluble alkyne and azide reactants and should thus be performed in an aqueous medium using a water-soluble catalyst. Important limitations for

Miniemulsion polymerization as a versatile tool for the synthesis of functionalized polymers

• Daniel Crespy and
• Katharina Landfester

Beilstein J. Org. Chem. 2010, 6, 1132–1148, doi:10.3762/bjoc.6.130

• with a water-soluble catalyst [72]. The reaction was faster when the oil-soluble catalyst was used. Finally, helical substituted polyacetylene could be efficiently polymerized in direct miniemulsion to yield a latex displaying intense circular dichroism [73]. Particles from 60 to 400 nm could be