Recent Advances in Transition-Metal-Catalyzed C–H Alkylation with Three-Membered Rings

Transition-metal-catalyzed alkylation of (hetero)­arenes with three-membered carbo-/heterocycles involving C–H activation and ring scission has been greatly developed over the past few years. The chelation-assisted strategies for controlling the reactivity and site selectivity in these protocols include the use of nitrogen-containing directing groups, pre-existing functional groups, and a Catellani-type intermediate, thereby providing rapid access to numerous oxygen- or nitrogen-containing heterocyclic ring systems. This review gives an update in the area of various catalytic methodologies and applications in the total synthesis of natural products involving these three-membered rings as alkylating reagents, which are classified into the following three categories on the basis of the employed directing strategies: (i) directed by nitrogen-containing directing groups, (ii) directed by pre-existing groups, and (iii) directed by aryl-NBE intermediates (Catellani-type cascade reaction).