The mechanism for allylic substitution is the same as the chain mechanism for alkane halogenations 1. Chain-Initiating Step high temp CI Cl r2 CI or hy 2. Chain-Propagating step H2=CHCH3 CI H2C= CHCH2°+HCl H2C=cHcH2°+Cl2一 H2C=CHCH2Cl+ ClThe mechanism for allylic substitution is the same as the chain mechanism for alkane halogenations 1. Chain-Initiating Step Cl Cl high temp or hv 2 Cl H2 C CHCH3 2. + Cl H2 C CHCH2 + HCl Chain-Propagating step H2 C CHCH2 + Cl 2 H2C CHCH2Cl + Cl