Exogenous Ligand-Free NiH-Catalyzed Hydroacylation of Aryl Alkenes with Aroyl Fluorides
Jihye Kim, Jieun Jang, Yoonho Lee and Kwangmin Shin*
*Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea, Email: kmshinskku.edu
J. Kim, J. Jang, Y. Lee, K. Shin, Org. Lett., 2022, 24, 5412-5416.
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A nickel hydride-catalyzed hydroacylation of aryl alkenes using aroyl fluorides proceeds without recourse to an exogenous ligand under mild conditions. The synthetic utility of the present method is demonstrated by a glovebox-free, gram-scale reaction and late-stage derivatizations of complex molecules.
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General Procedures for Hydroacylation of Aryl Alkenes with Aroyl Fluorides
In an argon-filled glovebox, an oven-dried screw-cap reaction tube equipped with a magnetic stir bar was charged with NiCl2•DME (6.6 mg, 0.03 mmol, 15 mol%) and K3PO4 (127.4 mg, 0.60 mmol, 3.0 equiv). DMF solvent (1.6 mL) was added via syringe and the resulting mixture was stirred for 10 min. (EtO)3SiH (40 µL, 0.22 mmol, 1.1 equiv) was added via micropipette and the reaction mixture was further stirred for 5 min before the addition of aryl alkene (0.20 mmol, 1.0 equiv) and aroyl fluoride (0.30 mmol, 1.5 equiv). Then, the remaining DMF solvent (0.4 mL) was added while rinsing the wall of the reaction tube. The reaction vessel was sealed with a screw cap, removed from the glovebox, and allowed to stir at room temperature for 24 h. After this time, saturated aqueous NaHCO3 solution (ca. 5 mL) was added to quench the reaction. Then the aqueous layer was extracted with Et2O (ca. 5 mL x 3). The combined organic layers were dried over MgSO4, filtered, and concentrated under reduced pressure. The crude reaction mixture was purified by silica column chromatography or preparative TLC on silica gel to obtain the desired hydroacylation product.