Recent trends in catalytic sp3 C–H functionalization of heterocycles†
Heterocycles are a ubiquitous substructure in organic small molecules designed for use in materials and medicines. Recent work in catalysis has focused on enabling access to new heterocycle structures by sp3 C–H functionalization on alkyl side-chain substituents—especially at the heterobenzylic position—with more than two hundred manuscripts published just within the last ten years. Rather than describing in detail each of these reports, in this mini-review we attempt to highlight gaps in existing techniques. A semi-quantitative overview of ongoing work strongly suggests that several specific heterocycle types and bond formations outside of C–C, C–N, and C–O have been almost completely overlooked.