Furthermore, the azetidine can serve as bioisosteric replacements for pyrrolidine, piperidine, and the phenyl ring. For instance, in the study of the 5-HT2C agonist (Figure , last example), replacing piperidine with azetidine led to enhanced potency. However, despite these advantages, azetidine remains relatively underexplored in drug discovery campaigns compared to its ubiquitous congeners, pyrrolidine and piperidine, likely due to the significant synthetic challenges. Generally, state-of-the-art methods to access functionalized azetidines involve either constructing the azetidine ring or modifying an existing azetidine ring. However, many of these pioneering methods are constrained by their linear nature, necessitating a distinctive synthetic sequence for each analogue. Comparatively, the modular strategy, which leverages azetidinylation reagents and the vast existing library of nucleophiles, is highly attractive. For example, Baran group reported the strain-release strategy based on 2e -logic, and MacMillan group disclosed a free-radical deoxygenative coupling strategy based on 1e -logic. Their methods can conveniently access 3-mono substituted azetidines (Figure , pathway a). Carreira group pioneered the use of acceptor azetidines for the addition of nucleophiles, with the electron-withdrawing group (EWG) presented in the product allowing for further derivatization (Figure , pathway b). This strategy represents an efficient method for accessing functionalized 3-alkyl azetidines. Bull and Trudell groups investigated 3-aryl azetidinol as azetidinylation reagents (Figure , pathway c). In Bull's studies, the Cbz protecting group of the azetidine was proposed to play a crucial role in stabilizing the generated carbocation intermediate, while other protecting groups, such as Boc and Ph2CH, did not afford any products. Besides, electron-rich aryl groups were required for reactivity, and the coupling partners were limited to electron-rich aromatics, primary and secondary alcohols, as well as electron-poor phenols. In Trudell's studies, only arenes were used as nucleophiles to couple with N-Boc-protected 3-aryl azetidinol via Friedel-Crafts chemistry. Therefore, it is highly anticipated to develop a more general method to produce these underexplored functionalized 3-aryl azetidines.