Advances and developments in transition metal-free benzylic C(sp 3 )–H activation/functionalization reactions

)-H activation/functionalization bond formation can be carried out in the presence of organic/inorganic peroxides, bases, acids, and other radical initiators. These radical transformations also occur under photochemical and electrochemical conditions. In this review, we highlight the C-H activation/annulation or C-H activation/functionalization reactions of benzylic carbon atoms in the presence of non-metal catalysts or promoters or without any catalyst.