The role of silver additives in gold-mediated C–H functionalisation

• Scott R. Patrick,
• Ine I. F. Boogaerts,
• Sylvain Gaillard,
• Alexandra M. Z. Slawin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2011, 7, 892–896, doi:10.3762/bjoc.7.102

• full conversion to product (entries 7 and 8), while the nature of the silver counter ion led reactivity to decrease in the order Ag2O > AgI > AgO, AgBF4, AgCl > Ag2CO3, AgOCOCF3 > AgNO3 > AgBr. Electronic effects can explain the general reactivity-decreasing trend on going from AgF to AgBr, but steric

Isotopic labelling studies for a gold-catalysed skeletal rearrangement of alkynyl aziridines

• Paul W. Davies,
• Nicolas Martin and
• Neil Spencer

Beilstein J. Org. Chem. 2011, 7, 839–846, doi:10.3762/bjoc.7.96

• rearrangement reaction. Cycloisomerisation of 15 in the skeletal rearrangement reaction. Revised mechanism for the formation of 2,4-isomers by skeletal rearrangement. Synthesis of alkynyl aziridines 30 and 31. Electronic effects on the outcome of the skeletal rearrangement processes. Mechanistic rationale for

Alkene selenenylation: A comprehensive analysis of relative reactivities, stereochemistry and asymmetric induction, and their comparisons with sulfenylation

• Vadim A. Soloshonok and
• Donna J. Nelson

Beilstein J. Org. Chem. 2011, 7, 744–758, doi:10.3762/bjoc.7.85

• the degree of substitution on C=C or upon substituent electronic effects. Electronic and steric effects influencing asymmetric induction, stereochemistry, regiochemistry, and relative reactivities in the addition of PhSeOTf to alkenes are compared and contrasted with those of PhSCl. Keywords: alkene

• selenenylation; asymmetric synthesis; calculations; electronic effects; regioselectivity; relative reactivities; steric effects; Introduction Electrophilic addition to alkenes is one of the most fundamental, generalized, and versatile methods for selective functionalization of hydrocarbons [1]. Despite recent

• these reactions have not been completely understood [29][33]. A more detailed analysis of steric and electronic effects might provide helpful mechanistic insights to clarify this practically important issue. Previously, we demonstrated that additions to alkenes, which proceed through cyclic 3-membered

Kinetic evaluation of the solvolysis of isobutyl chloro- and chlorothioformate esters

• Malcolm J. D’Souza,
• Matthew J. McAneny,
• Dennis N. Kevill,
• Jin Burm Kyong and
• Song Hee Choi

Beilstein J. Org. Chem. 2011, 7, 543–552, doi:10.3762/bjoc.7.62

• could have an impact on any potential steric or electronic effects, due to presence of the isobutyl group, on the specific rates of reaction. In this article we present determinations of the specific rates of reaction for isobutyl chloroformate (iBuOCOCl, 1) at 40.0 °C and of isobutyl chlorothioformate

Anion–π interactions influence pK_a values

• Christopher J. Cadman and
• Anna K. Croft

Beilstein J. Org. Chem. 2011, 7, 320–328, doi:10.3762/bjoc.7.42

• reaction. The five different substituents were chosen to span the range of electronic effects that could be invoked as a neighbouring effect. The identity of the products 2–5 was confirmed through melting point, 1H and 13C NMR spectral data, IR and MS (Supporting Information File 2). The 8-(4-methylphenyl

Palladium-catalyzed formation of oxazolidinones from biscarbamates: a mechanistic study

• Benan Kilbas and
• Metin Balci

Beilstein J. Org. Chem. 2011, 7, 246–253, doi:10.3762/bjoc.7.33

• proposed mechanism of oxazolidinone formation [3], the first step is complex formation between the metal and olefin. Steric and electronic effects of the olefin determine the stability of the complex. For example, bulky groups decrease the stability of the complex via steric interactions, while electron

The intriguing modeling of cis–trans selectivity in ruthenium-catalyzed olefin metathesis

• Naeimeh Bahri-Laleh,
• Raffaele Credendino and
• Luigi Cavallo

Beilstein J. Org. Chem. 2011, 7, 40–45, doi:10.3762/bjoc.7.7

• energetics of the basic CM reaction. Steric or electronic effects that would arise from more complex olefins would add to the prototype energy profile investigated here. Finally, for the sake of brevity, we will focus only on the productive CM of propene with the Ru–propylidene bond, while degenerate propene

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

• corresponding α-compounds can be made by an indirect route: Opening of a β-talo configured epoxide followed by C2 epimerisation. The very good regioselectivity in the epoxide-opening reaction indicates that steric and/or electronic effects favouring attack at C1 over C2 are more important than other factors

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

Ring-alkyl connecting group effect on mesogenic properties of p-carborane derivatives and their hydrocarbon analogues

• Aleksandra Jankowiak,
• Piotr Kaszynski,
• William R. Tilford,
• Kiminori Ohta,
• Adam Januszko,
• Takashi Nagamine and
• Yasuyuki Endo

Beilstein J. Org. Chem. 2009, 5, No. 83, doi:10.3762/bjoc.5.83

• consistent with data for pairs –CH2R/–OR, the effect of orientation of the carboxy group on mesophase stability is opposite. Therefore, steric arguments alone cannot explain the observed trend for these analogues. Electronic effects also cannot sufficiently explain the observed trend in mesophase stability

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