Reactions of Olefin Complexes with Nucleophiles

Coordination of an olefin molecule to the metal leads to its activation. This facilitates reactions of alkenes with various compounds. The coordinated olefin may have nucleophilic as well as electrophilic properties, and therefore may react in the first case with electrophiles, and in the second case with nucleophiles. Thus, either the central atom or the alkene may undergo nucleophilic attack. In the case of weak TT-olefin Cu(I) and Ag(I) complexes, even weak nucleophiles attack metal ions. 

In copper and silver olefin compounds, alkenes readily undergo exchange. Gold compounds are more stable, and their olefins react with nucleophiles. The compound Au2Cl2(cw-2-butene) reacts with D2O to give 2-butanone. The following d and d electron complexes readily react with nucleophiles Pd(II), Pt(II), Fe(II), etc. 

Reactions involving nucleophilic attack on Pd(II) and Pt(II) complexes are best known. For example, cyclooctadiene complexes react according to equation (6.102). Analogous reactions involving diene Pd(II) and Pt(II) complexes also take place with other nucleophiles. 

Products of reactions with R2NH, j8-diketones, ethyl acetylacetate MeCOCH2COOEt, and diethyl malonate CH2(COOEt)2 are as follows  

The nucleophile may coordinate to the metal as in the Pt(II) acetylacetonate complex, which reacts with triphenylphosphine according to equation (6.104). 

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