Stereospecific Copper‐Catalyzed CH Allylation of Electron‐Deficient Arenes with Allyl Phosphates

Abstract

Rapid and concise: The title reaction proceeds via copper complexes in a highly stereospecific manner (see scheme; acac=acetylacetonate, phen=1,10‐phenanthroline, TBS=tBuMe2Si). The catalysis provides a rapid and concise route to allylarenes that contain fluorinated aromatic cores of an electron‐deficient nature.

Regio‐ and Stereocontrolled Introduction of Secondary Alkyl Groups to Electron‐Deficient Arenes through Copper‐Catalyzed Allylic Alkylation

“…[11] Herein we report a Cu-catalyzed allylic alkylation of electron-deficient heteroarenes with internal secondary allylic phosphates, which proceeded with excellent g-regioselectivity and E-stereoselectivity. [12][13][14][15] This copper catalyst system was similarly applicable to fluoroarenes. Furthermore, the reaction of enantioenriched secondary allylic phosphates proceeded with 1,3-anti stereoselectivity to afford the corresponding alkylated (hetero)arenes with a controlled secondary stereogenic center.…”

Direct Palladium‐Catalyzed Intermolecular Allylation of Highly Electron‐Deficient Polyfluoroarenes

“…Introduction of Cs 2 CO 3 (1.2 equiv) to this catalytic system significantly improved the reaction efficiency and gave 87 % yield ( Table 1, entry 4), while other bases and copper salts were less effective ( Table 1, entries 6-11). In addition, Pd(OAc) 2 /PPh 3 are essential for the reaction, because the absence of either of them failed to give any desired product, and therefore ruled out the possibility that copper catalyzes this reaction under our present reaction conditions [15] (Table 1, entries 13 and 14). Further optimization showed that the best yield of isolated product (96 %) was afforded by decreasing the Pd(OAc) 2 loading to 5 mol % with use of Ph 3 P (10 mol %) and CuI/phen (5 mol %; Table 1, entry 15).…”

“…This approach provides a highly efficient protocol for the preparation of a wide range of allyllated polyfluoroarene compounds. [15] Initially, the reaction of pentafluorobenzene 1 with cinnamyl methyl carbonate 2 was investigated in the presence of Pd(OAc) 2 (10 mol %) and PPh 3 (20 mol %) in toluene at 120 8C. This reaction provided only a trace amount of allylated pentafluorobenzene (Table 1, entry 1).…”

Synthesis of Alkylated Polyfluorobenzenes through Decarboxylative Giese Addition of Aliphatic N-Hydroxyphthalimide Esters with Polyfluorostyrene

“…5 However, methods to access alkylated polyfluorobenzenes have been relatively less developed. Conventional strategies typically involve coupling polyfluoroaryls with alkenes, 6 hydrazones, 7 benzyl, 8 allyl, 9 propargyl, 10 or alkyl groups. 11 While, the direct construction of alkylated polyfluorobenzenes using commercially available polyfluorostyrene was rarely reported.…”