Facile isomerization of silyl enol ethers catalyzed by triflic imide and its application to one-pot isomerization–(2 + 2) cycloaddition

• Kazato Inanaga,
• Yu Ogawa,
• Yuuki Nagamoto,
• Akihiro Daigaku,
• Hidetoshi Tokuyama,
• Yoshiji Takemoto and
• Kiyosei Takasu

Beilstein J. Org. Chem. 2012, 8, 658–661, doi:10.3762/bjoc.8.73

• ) cycloaddition of silyl enol ethers with acrylates generating substituted cyclobutanes [10]. We are intrigued that the isomerization of silyl enol ethers and successive (2 + 2) cycloaddition could be promoted by Tf2NH in a one-pot reaction. When 1a was treated with Tf2NH (1 mol %) under the isomerization

Branching out at C-2 of septanosides. Synthesis of 2-deoxy-2-C-alkyl/aryl septanosides from a bromo-oxepine

• Supriya Dey and
• Narayanaswamy Jayaraman

Beilstein J. Org. Chem. 2012, 8, 522–527, doi:10.3762/bjoc.8.59

• substrate presenting two acrylates within the molecule, styrene, and α-methyl styrene (Scheme 1). Reactions with these substrates also afforded the diene products 4–7, in good yields. The anticipated two Heck coupling reactions with the substrate that presents two acrylates, could not be achieved, rather

• . Conclusion The present study illustrates the effective application of synthetically useful bromo-oxepine for the preparation of hitherto unknown 2-deoxy-2-C-alkyl/aryl septanoside derivatives. C–C bond forming Heck, Suzuki and Sonogashira coupling reactions, with appropriate acrylates, arylboronic acids and

Chiral gold(I) vs chiral silver complexes as catalysts for the enantioselective synthesis of the second generation GSK-hepatitis C virus inhibitor

• María Martín-Rodríguez,
• Carmen Nájera,
• José M. Sansano,
• Abel de Cózar and
• Fernando P. Cossío

Beilstein J. Org. Chem. 2011, 7, 988–996, doi:10.3762/bjoc.7.111

• of acrylates as dipolarophiles has only been explored with the 2-thienyliminoesters 6a. Therefore, based on our experience of silver(I)- and gold(I)-catalyzed 1,3-DC involving azomethine ylides derived from α-iminoester 6b and tert-butyl acrylate, we selected a series of known chiral phosphoramidite

• the approach of the mentioned dipolarophile. Conclusion In this work the complexity of the 1,3-DC reaction of azomethine ylides and dipolarophiles (in this case acrylates) was demonstrated. There are many parameters to control and a small variation can cause a dramatic effect in the overall

• enantiodiscrimination of the process. The temperature does not equally affect silver(I) and gold(I) catalysts. The effect of the heterocycle remains crucial in these transformations because, originally, the enantioselectivity of the reaction between methyl benzylideneiminoglycinate and alkyl acrylates failed in the

Regioselective ester cleavage during the preparation of bisphosphonate methacrylate monomers

• Kamel Chougrani,
• Gilles Niel,
• Bernard Boutevin and
• Ghislain David

Beilstein J. Org. Chem. 2011, 7, 364–368, doi:10.3762/bjoc.7.46

• (meth)acrylates, and can be readily polymerized by emulsion or solution methods [8][9]. Polymers with some phosphonate functionality have long been established as excellent adhesives and anti-corrosion compounds [10][11][12][13][14][15][16][17], however, there has been very little investigation into the

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

• terminated by carboxy groups (Scheme 5). These CM reactions were also extended to acrylates that contained a dendronic group. This strategy allowed constructing dendrimers from one generation to the next. Thus, iteration allows synthesizing a dendrimer of second generation with 81 olefin termini from a

The catalytic performance of Ru–NHC alkylidene complexes: PCy₃ versus pyridine as the dissociating ligand

• Stefan Krehl,
• Diana Geißler,
• Sylvia Hauke,
• Oliver Kunz,
• Lucia Staude and
• Bernd Schmidt

Beilstein J. Org. Chem. 2010, 6, 1188–1198, doi:10.3762/bjoc.6.136

• loading of 2 mol % was sufficient to achieve a 92% conversion within one hour (Figure 4). Ring closing metathesis of acrylates Having established the beneficial effect of acetic acid for the ring closing metathesis reaction of allyl ether 1 catalyzed by H, we were interested to see if a similar effect

• ). Toluene was preferred over dichloromethane, because reactions are more conveniently conducted at elevated temperatures in this solvent. The acrylates 3 investigated in ring closing metathesis reactions with catalysts D, E and H are listed in Figure 5, together with the resulting unsaturated lactones 4

• . Results for the ring closing metathesis of acrylates 3a–g are summarized in Table 2. Lactones 4b–f [50] are accessible in preparatively useful yields with catalyst loadings of 2.5 mol % to 5.0 mol % if catalysts D and E are used. Conversions observed with catalyst H under otherwise identical conditions

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

• [32]. For a batch process with an initiator in the aqueous phase, it was found that the copolymerization followed the Mayo–Lewis equation despite the huge difference of solubility of the monomers in the aqueous continuous phase. Fluorinated monomers (fluoroalkyl acrylates) could be easily polymerized

Novel 2-(ω-phosphonooxy-2-oxaalkyl)acrylate monomers for self-etching self-priming one part adhesive

• Joachim E. Klee and
• Uwe Lehmann

Beilstein J. Org. Chem. 2010, 6, 766–772, doi:10.3762/bjoc.6.95

• acrylate and formaldehyde, and subsequent etherification of the obtained product with diols and phosphorylation using POCl3. The polymerization enthalpy of 2-(ω-phosphonooxy-2-oxaalkyl)acrylates 3 as measured by DSC ranges from −29 to −53 kJ·mol−1. The shear bond strength of adhesive compositions 4

• , comprising of polymerizable acids 3, ranges from 5.8 to 19.3 MPa on enamel and from 8.7 to 16.9 MPa on dentin. Keywords: adhesion to enamel and dentin; hydrolysis stable 2-(ω-phosphonooxy-2-oxaalkyl)acrylates; phosphorylation using POCl3; polymerization enthalpy; shear bond strength; Introduction Dental

• moieties takes place in a similar manner to carboxylic acid esters, and to establish whether acidic molecules with 2-(ω-phosphonooxy-2-oxaalkyl)acrylate moieties exhibit the same adhesive performance as their ester analogues. Results and Discussion A series of novel 2-(ω-phosphonooxy-2-oxaalkyl)acrylates 3

Synthesis, characterization and photoinduced curing of polysulfones with (meth)acrylate functionalities

• Cemil Dizman,
• Sahin Ates,
• Lokman Torun and
• Yusuf Yagci

Beilstein J. Org. Chem. 2010, 6, No. 56, doi:10.3762/bjoc.6.56

• polymerization and conversion were evaluated. Thermal properties of the photochemically cured films were studied by differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). Keywords: acrylates; photoinitiated polymerization; polysulfone; UV-curable oligomers; Introduction Polysulfones

• range capable of inducing rapid polymerization to form insoluble networks [16]. Because of their high reactivity leading to fast polymerization [17], multifunctional (meth)acrylates are the most commonly used monomers for many applications [18][19][20][21][22]. The activity of the (meth)acrylates