The application of a monolithic triphenylphosphine reagent for conducting Appel reactions in flow microreactors

• Kimberley A. Roper,
• Heiko Lange,
• Anastasios Polyzos,
• Malcolm B. Berry,
• Ian R. Baxendale and
• Steven V. Ley

Beilstein J. Org. Chem. 2011, 7, 1648–1655, doi:10.3762/bjoc.7.194

• left on the monolith. This bromine could be present in hard-to-access active sites within the polymeric structure of the monolith, but could also be accounted for by some of the late intermediates in pathway B (10–15 in Scheme 1). The conversion of a particular substrate did not decrease with continued

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

• model systems and in enzyme active sites, in which the interacting species are brought in close proximity to one another, these effects are often amplified because of the reduction of the contribution of entropic factors. This is recognised as a proximity effect and can be measured by an effective

Stereoselectivity of supported alkene metathesis catalysts: a goal and a tool to characterize active sites

• Christophe Copéret

Beilstein J. Org. Chem. 2011, 7, 13–21, doi:10.3762/bjoc.7.3

• Abstract Stereoselectivity in alkene metathesis is a challenge and can be used as a tool to study active sites under working conditions. This review describes the stereochemical relevance and problems in alkene metathesis (kinetic vs. thermodynamic issues), the use of (E/Z) ratio at low conversions as a

• tool to characterize active sites of heterogeneous catalysts and finally to propose strategies to improve catalysts based on the current state of the art. Keywords: active sites; metathesis; stereoselectivity; supported catalysts; Introduction Achieving high selectivity and, in particular

• (styrenyl systems or alkenes with electron withdrawing substituents) [19][20][21]. Here the discussion will focus on the stereoselectivity of alkene metathesis in order to delineate the current state of the art in the case of heterogeneous catalysts and show how it can be used to characterize active sites

Flow through reactors for organic chemistry: directly electrically heated tubular mini reactors as an enabling technology for organic synthesis

• Ulrich Kunz and
• Thomas Turek

Beilstein J. Org. Chem. 2009, 5, No. 70, doi:10.3762/bjoc.5.70

• . We chose a polymer catalyst because polymers are well defined materials which can be functionalized easily with many active groups. This leads to a wide variety of materials, including composites, suitable as catalysts or for anchoring active sites leading to a large number of composites [17][18][19

Synthesis and enzymatic evaluation of 2- and 4-aminothiazole- based inhibitors of neuronal nitric oxide synthase

• Graham R. Lawton,
• Haitao Ji,
• Pavel Martásek,
• Linda J. Roman and
• Richard B. Silverman

Beilstein J. Org. Chem. 2009, 5, No. 28, doi:10.3762/bjoc.5.28

• useful nNOS-selective inhibitors is a difficult task as the substrate for all three isoforms is L-arginine, and so they have similar active sites. In recent years, we have developed several potent and highly selective inhibitors of nNOS that have solved this problem by exploiting subtle differences among