Triazole–Au(I) complex as chemoselective catalyst in promoting propargyl ester rearrangements

• Dawei Wang,
• Yanwei Zhang,
• Rong Cai and
• Xiaodong Shi

Beilstein J. Org. Chem. 2011, 7, 1014–1020, doi:10.3762/bjoc.7.115

• (Scheme 2a) [34]. Both experimental and theoretical investigations confirmed the reversibility between allene and propargyl ester due to effective activation of both functional groups by the Au(I) catalysts. As a result, it was extremely challenging to obtain the allene intermediates with good yields

Michael-type addition of azoles of broad-scale acidity to methyl acrylate

• Sławomir Boncel,
• Kinga Saletra,
• Barbara Hefczyc and
• Krzysztof Z. Walczak

Beilstein J. Org. Chem. 2011, 7, 173–178, doi:10.3762/bjoc.7.24

• acrylate was observed. Nevertheless, decreased yields for azole adducts when DBU or NaH were used as catalysts at elevated temperature could originate from a reversibility of the Michael reaction since unreacted azoles were isolated. This observation is in a good agreement with our recent findings for

Carbasugar analogues of galactofuranosides: α-O-linked derivatives

• Jens Frigell and
• Ian Cumpstey

Beilstein J. Org. Chem. 2010, 6, 1127–1131, doi:10.3762/bjoc.6.129

• reversibility requires an antiperiplanar relationship between the nucleophile and the epoxide oxygen in the product immediately after reaction. From a given half-chair conformation of the epoxide, nucleophilic attack results in either a chair (with the substituents trans-diaxial) or a skew-boat conformation

Self-assembly and semiconductivity of an oligothiophene supergelator

• Pampa Pratihar,
• Suhrit Ghosh,
• Vladimir Stepanenko,
• Sameer Patwardhan,
• Ferdinand C. Grozema,
• Laurens D. A. Siebbeles and
• Frank Würthner

Beilstein J. Org. Chem. 2010, 6, 1070–1078, doi:10.3762/bjoc.6.122

• in the conformational order in the assembled state [23]. To test the reversibility of the self-assembly process, variable temperature UV-vis experiments were performed in n-heptane. These clearly showed that when the temperature was gradually raised from 45 °C to 85 °C, the spectral pattern changed

A perfluorocyclopentene based diarylethene bearing two terpyridine moieties – synthesis, photochemical properties and influence of transition metal ions

• Falk Wehmeier and
• Jochen Mattay

Beilstein J. Org. Chem. 2010, 6, No. 53, doi:10.3762/bjoc.6.53

• reversibility. It was shown that the presence of various transition metal ions significantly influences the photochromism of the bridging unit: While iron(II)-ions completely inhibit the photochromic reaction, cobalt(II) and nickel(II) appear to slow down the photoreaction considerably. Zinc(II)-ions, on the

Reversible intramolecular photocycloaddition of a bis(9-anthrylbutadienyl)paracyclophane – an inverse photochromic system. (Photoactive cyclophanes 5)

• Henning Hopf,
• Christian Beck,
• Jean-Pierre Desvergne,
• Henri Bouas-Laurent,
• Peter G. Jones and
• Ludger Ernst

Beilstein J. Org. Chem. 2009, 5, No. 20, doi:10.3762/bjoc.5.20

• the same setup; the spectra were recorded at various time intervals, within 10 min, at ambient temperature. Reversibility of the formation of the photoproduct 4 at 400 nm (40 min) and photodissociation of 4 at 306 nm in MCH. 1H NMR spectra (400 MHz, CDCl3). A: Compound 2, B: Compound 4. Proposed

Synthesis and redox behavior of new ferrocene- π-extended- dithiafulvalenes: An approach for anticipated organic conductors

• Abdelwareth A. O. Sarhan,
• Omar F. Mohammed and
• Taeko Izumi

Beilstein J. Org. Chem. 2009, 5, No. 6, doi:10.3762/bjoc.5.6

• , although displaying a good extent of chemical reversibility in cyclic voltammetry and consuming one electron/molecule (EOx2 = +0.905 V), affords a dirty green solution which no longer exhibits a cyclic voltammetric profile attributable to the generation of redox congeners of 8. This proves that the

Reagent controlled addition of chiral sulfur ylides to chiral aldehydes

• Varinder K. Aggarwal and
• Jie Bi

Beilstein J. Org. Chem. 2005, 1, No. 4, doi:10.1186/1860-5397-1-4

• reversibility in betaine formation, which impacted on the stereocontrol at the C2 position. Introduction The reaction of chiral sulfur ylides with carbonyl compounds, operating in either a catalytic or stoichiometric mode, have emerged as a useful and powerful method in the arsenal of asymmetric

• transformations.[1] Indeed, near perfect levels of asymmetric induction with high diastereocontrol have been achieved with aromatic aldehydes (Scheme 1). In such reactions, the C1 stereochemistry is controlled by ylide conformation, face selectivity, and the degree of reversibility in formation of the anti

• betaine (high reversibility results in low stereocontrol) whilst the C2 stereochemistry is controlled by the degree of reversibility in syn betaine formation (high reversibility leads to high diastereocontrol in favor of the trans epoxide).[2] We questioned whether the high level of reagent control