Nucleophilic catalysis ethylene oxide, reaction

As we ve just seen nucleophilic ring opening of ethylene oxide yields 2 substituted derivatives of ethanol Those reactions involved nucleophilic attack on the carbon of the ring under neutral or basic conditions Other nucleophilic ring openings of epoxides like wise give 2 substituted derivatives of ethanol but either involve an acid as a reactant or occur under conditions of acid catalysis... 

Key Words Ethylene oxide, Ethylene, Epoxidation, Silver, Cl promotion, Cs promotion. Promotion, Selectivity, Oxametallacycle, Adsorption, Desorption, Chemisorption, Activation energy, Ag-O bond. Reaction mechanism, Oxidation, Cyclisation, Heterogeneous catalysis, Selective oxidation, Eletrophilic oxygen. Nucleophilic oxygen. Subsurface O atoms, Ag/a-A Oj catalyst. 2008 Elsevier B.V. 

To illustrate the inner-sphere characteristics of the CH activation chemistry, an analogy can be made between CH activation by coordination of an alkane CH bond to a metal center and the known catalysis resulting from coordination of olefins via the CC double bond (note that the nature of the orbitals involved in bonding are quite different). It is well known that coordination of olefins to electrophilic metal centers can activate the olefin to nucleophilic attack and conversion to organometallic, M-C, intermediates. The M-C intermediates thus formed can then be more readily converted to functionalized products than the uncoordinated olefin. An important example of this in oxidation catalysis is the Wacker oxidation of ethylene to acetaldehyde. In this reaction, catalyzed by Pd(II) as shown in Fig. 7.14, ethylene is activated by coordination to the inner-sphere of an electrophilic Pd(II) center. This leads to attack by water and facile formation of an organometallic, palladium alkyl intermediate that is subsequently oxidized to acetaldehyde. The reduced catalyst is reoxidized by Cu(II) to complete the catalytic cycle. The Wacker reaction is very rapid and selective and it is possible to carry out the reaction is aqueous solvents. This is largely possible because of the favorable thermodynamics for coordination of olefins to transition metals that can be competitive with coordination to the water solvent. The reaction is very selective presumably because the bonds of the product (po-... 

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