Additions to unsaturated systems

TABLE 5. Survey of sulfonyl halide additions to unsaturated systems and hydrogen halide eliminations to unsaturated sulfones... 

P. B. de la Mare and R. Bolton, Electrophilic Additions to Unsaturated Systems, 2nd ed., Elsevier, New York, 1982. 

De la Mare, P.B.D. Bolton, R. Electrophilic Additions to Unsaturated Systems. Elsevier Scient. Publ. Co. Amsterdam, Holland, 1982 p 247. 

Quite generally addition to unsaturated systems takes place, e.g. to >C=0, >C=N—, — G=N, — N=0, but >C=C< and —C=C— do not react. The mechanism of the addition is as follows the Grignard reagent is added on in the form of its two components R and MgHal in the case of the 0=0-double bonds the Mg-containing constituent always unites with the oxygen, R always with the carbon. 

DE LA MARE, p. B. D. and BOLTON, J. ElcctrophiUc Addition to Unsaturated Systems (Elsevier, 2nd Edition, 1982). 

The second pathway (step 4, 3b, p. 304) has been proposed for the addition to unsaturated systems which are electron deficient. This is pictured as arising from attack of the electron in the n orbital of the n,ir state on the electron-deficient olefin, which is then followed by bond formation.32... 

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