Reactivity in metathesis

The cause for the high P-P bond reactivity in metathesis and addition reactions of P-phosphino-NHPs was further rationalized when it was established that attack of electrophiles at the PR -substituent facilitates bond cleavage reactions by further boosting the polarization and weakening of the P-P bond and may thus be considered to induce an autocatalytic activating effect [77],... 

Both the long C-C bond distance (1.50 A) and the very short Pt—C distances (2.0 A) indicate the strong interaction between the adsorbed molecule and the three platinum surface atoms. The covalent Pt—C distance would be 2.2 A. The shorter metal-carbon distances indicate multiple metal-carbon bonding that may be carbene or carbyne-like. Compounds with these types of bonds exhibit high reactivity in metathesis and in other addition reactions The carbon-carbon single bond distance indicates that the molecule is stretched as much as possible without breaking of this chemical bond. 

On the basis of substantial differences in the reactivity in metathesis, vinylsilanes can be divided into four general classes (Scheme 1) [20]. 

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