Cyano groups are strong electron withdrawing substituents which generally lower the nucleophilic reactivity of nearby nucleophilic centers. Thus P (CH20H30N) 3 is a much weaker nucleo-phile than Eta]? and even I'h,, I'. 1 A cyano-methyl substituent is expected to lower the nucleophilic reactivity more than a 2-cyanoethyl substituent, _ but not so strongly as 3. directly bonded cyano group. For example, the phosphorus atom in P (CN) 3'has lost ...
