our previous study , we carried out the reaction between iodobenzene (1a, 3.0 equiv) and 1-fluorododecane (2a, 1.0 equiv) in the presence of commercially available calcium metal (2.0 equiv) and tetrahydropyran (THP) (4.0 equiv) using a 1.5 mL stainless steel jar along with two stainless steel balls (diameter: 5 mm) in air. After ball milling (30 Hz) for 60 min with the aid of a heat gun as a temperature controller to ensure that internal temperature was 80 °C (for details, see the Supporting Information), the C(sp 3 )-F bond arylation product 3aa was successfully obtained in good yield (86%, Table , entry 1). When the reaction was carried out at room temperature without using a heat gun, the yield of 3aa decreased significantly (28%, Table 1, entry 2). Ether additives are supposed to coordinate to the calcium (II) center to form thermodynamically stable species, facilitating the formation of aryl calcium nucleophiles under mechanochemical conditions. In fact, the reaction did not proceed without the addition of THP (<5%, Table , entry 3). Using tetrahydrofuran (THF) resulted in a moderate yield (51%, Table , entry 4). However, the reaction was completely suppressed when dimethoxyethane (DME) was employed (<5%, Table 1, entry 5). Lowering the vibration frequency of ball milling resulted in a significant decrease in yield, indicating that mechanical impact played an essential role in this transformation (62%, Table 1, entry 6). Lower yields were obtained when reducing the amounts of 1a and calcium metal (61% and 41%, respectively, Table and). When the reaction was carried out using a 10 mL stainless-steel jar with two stainless-steel balls (diameter: 10 mm), a moderate yield of 3aa was obtained (66%, Table 1, entry 9). Considering the possibility of such cross-electrophile coupling catalyzed by transition metals derived from the stainless-steel milling jar and/or balls , we performed the reaction using a commercially available 10 mL zirconium oxide jar with two zirconium oxide balls (diameter: 10 mm), affording the desired arylation product 3aa in 43% yield (Table , entry 10). This result suggests that the C(sp 3 )-F bond arylation process does not involve a mechanism with transition metal catalysts. Notably, when the reaction was performed by employing magnesium instead of calcium, the generation of arylation product 3aa was not detected (<5%, Table , entry 11). In order to confirm the role of a ballmilling technique, we conducted the reaction in THP solution at 80 °C (Table , entry 12). We found that 3aa was not detected, and almost no conversion of 1a (3% conversion) was observed, suggesting that the mechanical impact provided by ball milling is essential for the generation of the aryl calcium nucleophile that subsequently reacts with alkyl fluoride 2a. The use of bromo-or chlorobenzene instead of 1a resulted in no product formation (Table , entries 13 and 14), which was due to the difficulties in generating the corresponding calcium nucleophiles. With the optimal conditions in hand, we then investigated the substrate scope. As shown in Table , we first focused on the scope of aryl iodides bearing different kinds of substituents. The introduction of a substituent such as methyl (1b), tert-butyl (1c), phenyl (1d), or diphenylamino (1e) groups at the pareposition on the phenyl ring did not affect the reactivity, affording the desired arylation products (3ba-3ea) in moderate to good yields (63-83%). Substrate bearing a methyl group on the meta-position (1f) also reacted under the mechanochemical conditions to deliver the target product 3fa in high yield (88%). Reaction with substrate having a sterically demanding substituent such as 2-isopropyl group (1g) proceeded smoothly to produce the corresponding product (3ga) in good yield (80%). We also found that the arylation with polycyclic aryl iodides (1h and 1i) was feasible and the desired products (3ha and 3ia) in good yields (69% and 85% yields, respectively). Unfortunately, in the presence of functional groups, such as methoxy (1j), ester (1k), or carbonyl (1l) groups, the reactions did not proceed. We then pursued to examine the substrate scope with respect to the alkyl fluorides (Table ). Alkyl fluoride bearing a phenyl group 2b reacted smoothly to afford the desired product 3ab in good yield (82%). We found that the presence of a trifluoromethyl group on the benzene ring (2c) did not interfere with the reaction, and only the C-F bond of the monofluoromethyl group located at the end of the alkyl chain was activated to generate the corresponding arylation product 3ac in good yield (86%). Functional groups such as a phenoxy group (2d), phenylthioether (2e), and alkenes (2f and 2g) were tolerated under the optimized conditions, providing the target products (3ad-3ag) in moderate to good yields (70-86%). It is equally important to mention the current limitations of this method, including the difficulty in coupling with alkyl fluorides bearing a benzyloxy group (2h) or thiophene moiety (2i), resulted in low yields of the desired products (3ah and 3ai, 21% and 20% yields, respectively). When secondary alkyl fluoride 2j was used, the corresponding arylation product was not detected.