Beta carbon atom

I), the substituent occurs on the carbon atom bearing the unpaired electron, and in this position it is able to provide resonance structures in which the unpaired electron appears on the substituent. The substituent consequently has the effect of stabilizing the radical, the extent of such stabilization depending, of course, on the capacity of the substituent for resonance. In product radical (II), the substituent is situated on the beta carbon atom, where it is unavailable for participation in resonating structures involving the odd electron. Consequently, the product radical (I) ordinarily will be more stable than... 

The carbonyl group of the ketones weakly deshields the geminal olefinic proton but strongly de-shields the cis and trans hydrogens bonded to the beta carbon atom. Its effect is similar to that of the unsaturated carbon atom of the nitrile (-C=N) functional group. 

The cracking pattern given by zinc di (4-methyl 2-pentyl) dithiophosphate is more informative, and the results obtained may be compared with those obtained by Legate and Burnham. Having two beta carbon atoms from which hydrogen may be removed, two olefins are likely to be formed, 4-methyl pentene-1 and 4- methyl pentene-2. 

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