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

• silanols derived from decomposed corresponding silyl ethers. The P-K reaction is known to be affected by steric and electronic effects within the cyclisation precursors. Therefore we prepared the following dimethyl vinyl- and allyl-silyl ethers with various groups attached to the terminus of the alkyne

Effect of transannular interaction on the redox- potentials in a series of bicyclic quinones

• Grigoriy Sereda,
• Jesse Van Heukelom,
• Miles Koppang,
• Sudha Ramreddy and
• Nicole Collins

Beilstein J. Org. Chem. 2006, 2, No. 26, doi:10.1186/1860-5397-2-26

• redox-potentials of bicyclo[2.2.2]octane-derived quinones will help in the design of new compounds with controlled biological activity. However, attempts to directly relate the reduction potentials of substituted triptycene-quinones to the electronic effects of substituents are often unsuccessful

• activity. However, attempts to directly relate the reduction potentials of substituted triptycene-quinones to the electronic effects of substituents are often unsuccessful. Thus, the negative shift of the reduction potential, caused by two methoxy-groups at the 5,8-positions (compound 2), was surprisingly

• difference may fall below the threshold that would warrant sufficient concentrations of the conformation B to account for the experimental redox-potential of 2. Yamamura and co-authors [3] also noticed that the reduction potential of the quinone 2 was higher than expected from the electronic effects of the

A superior P-H phosphonite: Asymmetric allylic substitutions with fenchol- based palladium catalysts

• Bernd Goldfuss,
• Thomas Löschmann,
• Tina Kop-Weiershausen,
• Jörg Neudörfl and
• Frank Rominger

Beilstein J. Org. Chem. 2006, 2, No. 7, doi:10.1186/1860-5397-2-7

• electronic effects,[3][4] regioselectivity in favor of the branched product is supported at strong donor-substituted (e.g. alkyl, O-alkyl) allylic positions. Frequently employed Pd-catalysts most often favor linear, nonchiral products (Scheme 1). Pfaltz et al. improved the yield of the chiral, branched