Sustainable, Oxidative, and Metal-Free Annulation.
Annulation has received steadily growing interest in the interplay with the increasing emphasis towards selective C-H bond functionalization reactions. Metal-free oxidative annulation through functionalization of inert and abundant C-H bonds offers great improvements in terms of atom- and step-economics as well as reduced waste production under mild reaction conditions. Annulation is considered to be a highly efficient strategy for the construction of cyclic molecules because at least two new bonds are formed within a single reaction step. The combination of annulation and direct C-H bond functionalization allows the efficient and straightforward synthesis of carbo- and heterocyclic molecules using simple and non-prefunctionalized precursors. This Concept highlights novel strategies and recent breakthroughs for metal-free annulation through C-H bond functionalization giving access to a variety of important structural motifs.
['Bering|Luis|L|http://orcid.org/0000-0003-1618-0782', 'Manna|Srimanta|S|http://orcid.org/0000-0002-3903-1256', 'Antonchick|Andrey P|AP|http://orcid.org/0000-0003-0435-9443']
metal-free annulation C−H bond functionalization green chemistry sustainable methods