Multiple-fold C-F bond functionalization for the synthesis of (hetero)cyclic compounds: fluorine as a detachable chemical handle

Although the demand for privileged (hetero)cyclic molecules continues to grow steadily in organic synthesis, drug discovery, agrochemical chemistry, materials science, etc., the innovative development of incredibly powerful techniques that allow facile (hetero)cycle assembly with structural complexity and diversity from ubiquitous starting materials is hardly keeping pace. Under this context, the straight activation of multiple notorious C-F bonds in poly- or perfluorine-containing compounds (PFCs), which are academically and practically readily accessible by fluorinations or fluorochemical industry, concomitant with further transformations has indeed become an emerging theme for the manufacture of usefully oligofluorinated or nonfluorinated cyclic skeletons. In this review, we highlighted the recent advances in this field by underpinning the cleaved C-F bond number during the defluorinative process, where the distinctive fluorine effects are the synthetic linchpins for tuning the reaction selectivity of PFCs and controlling reaction pathways for the anticipated annulation in a designed sense. Emphasis is placed on the function of fluorine as a detachable "chemical handle". This review aims to reveal specific research opportunities in the topics of C-F bond activation and heterocyclic chemistry.