Copper‐Catalyzed Homocoupling of Alkyl Halides in the Presence of Samarium

Abstract

By virtue of the reductive coupling reactivity of samarium, cuprous chloride can effectively catalyze the homocoupling of alkylhalides, including the Csp 3

Organic Synthesis with Elemental Lanthanides – Going Beyond Samarium and Ytterbium

“…Recently, Ni and Cu salts have been employed in combination with Sm metal in the homocoupling of a wide range of alkyl, aryl and benzyl halides 151 (Scheme 34). [65,66] The role of Sm was postulated to be the formation of low-valent Ni or Cu species. An organosamarium intermediate derived from metal insertion into the RÀ X bond was also postulated in the mechanism.…”

Access to Diarylmethanol Skeletons via a Samarium/Copper-Mediated Sequential Three-Component C–H Functionalization Reaction

“…However, although the direct use of samarium metal is more attractive for large-scale preparation while samarium diiodide shows extremely poor atom economy and high sensitivity to air and moisture in most cases, very few reactions were explored, probably due to the mild reactivity of samarium metal . In our recent investigation, the combined use of samarium reagents and transition metals including copper salts showed particular reactivity to the bond formation . As a common metal catalyst, the copper reagents have a great catalytic effect on the formation of C–C, C–O, and other bonds, with the advantages such as economical and practical with high recycling rate …”

Synthesis of Dibenzyls by Nickel-Catalyzed Homocoupling of Benzyl Alcohols

“…2 In general, these compounds were synthesized through the homocoupling reactions of benzylic halides under reductive conditions (Scheme 2a). [3][4][5][6][7][8] The substrate scope have been extended from bromides to iodide and chloride, and a wide range of catalyst proved to be effective, including nickel, 3 cobalt, 4 titanium, 5 copper, 6 iron, 7 and rhodium. 8 They were also be prepared through oxidative homocoupling reactions using organometallic species (e.g., R−M: M = Mg, Zn) as coupling partners (Scheme 2b).…”

“….8 mg (68%); white solid; mp: 111-113 °C.1 H NMR (400 MHz, CDCl 3 ):  = 7.05 (d, J = 8.1 Hz, 2 H),6.71 (dd, J = 8.1, 1.8 Hz, 2 H),6.63 (d, J = 1.8 Hz, 2 H),6.58 (t, J = 75.8 Hz, 2 H), 3.78 (t, J = 6.9 Hz, 4 H), 2.84 (s, 4 H), 1.28-1.17 (m, 2 H), 0.66-0.59 (m, 4 H), 0.35-0.30 (m, 4 H) 13. C NMR (100 MHz, CDCl 3 ):  = 150 4,.…”