Selectivity of the transformation

The use of Fenton s reagent in nonprotic solvents (MeCN, CH2C12) results in substantial changes in the reactivity and the selectivity of the transformations. Thus alkenes are stoichiometrically epoxidized in a nonstereoselective fashion by H202/Fe(acac)3 in acetonitrile (equation 218).489,528... 

D) The above methods rely on the selection of the transformed cells by making use of one of the properties listed above. Stoker and... 

Rearrangement was observed in the reaction of benzyl alcohol with xenon difluoride106, while deactivating substituents on the phenyl ring even improved the selectivity of the transformation and the yields of fluoromethoxy derivatives formed rose to 75-85% (Scheme 39). 

Tremendous improvement was achieved when 12 was used neat at higher electrolysis temperature. The yield as well as the selectivity of the transformation could be considerably ameliorated (Table 5.2). 

Rationalise the selectivity of the transformation of compound 4 into compound 5. 

The success of the plan outlined in Scheme 2.91 depended entirely upon the preliminary organization of carefully selected protecting groups in the starting compounds. The selectivity of the transformation for every step was thus secured and did not require additional protection or deprotection operations. This example nicely illustrates the power of utilizing the protective group manipulations introduced in this section. 

Even if the use of rare-earth phosphates in heterogeneous catalysis for fine chemicals has been reported from more that 20 years, those catalysts were little characterized. Recently, doping those catalysts with cesium salts has greatly improved the activity, selectivity of the transformation as well as the life time of the catalysts (refs. 1,2). 

The chiral substrate is available in optically pure form64 and the very high diastereofacial selectivity of the transformation allows an efficient, enantio- and stereoselective synthesis of highly functionalized bicyclic frameworks. As expected, the cycloaddition occurs on the face of the double bond opposite to the ring substituent. 

The use of solid catalysts for the production of fine chemicals has found a broad range of applications in the field of organic chemistry. In the liquid phase, where solvents are often used to solubilize reactants, facilitate heat transfer and avoid coke formation on the catalyst, the choice of the solvent is crucial, influencing both the activity of the catalyst and the selectivity of the transformation. 

The example design of a motion estimation application using the design script resulted in an architecture that can be compared with even the best manual designs. The careful selection of the transformation matrix produced an architecture with optimal I/O and control flow. Only control logic and I/O at the borders is needed, and the interface buffer sizes needed are very small. This shows that the proposed methodology and tools can indeed be used for complex real-life examples, with optimal results. 

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