Cobalt-Salen Catalyzed Electroreductive Alkylation of Activated Olefins

Abstract

Cobalt-Salen mediated electroreductive and regioselective alkylation of electron deficient olefins is reported in one step in an undivided electrochemical cell, in the presence of an iron rod as sacrificial anode. Although the reactivity depends on the class of alkyl halides, the reported study offers a green and expeditious electrosynthetic route for Csp3-Csp3 bond formation in mild conditions. This study also confirms the possible formation of the heterobinuclear cobalt-Salen-iron complex previously reported as the effective catalyst.

Recent Advances in C(sp3)–C(sp3) and C(sp3)–C(sp2) Bond Formation through Cathodic Reactions: Reductive and Convergent Paired Electrolyses

“…Condon et al published an electrocatalytic reductive Giese-type addition of simple alkyl bromides 34 to activated alkenes 35 with low to moderate yields using an in situ generated cobalt–Salen complex as the catalyst. 22 The reaction was performed under simple reaction conditions using constant current electrolysis in an undivided cell with a cheap nickel grid cathode and an iron-based sacrificial anode. The test of other sacrificial anodes resulted in lower yields, indicating a putative role of in situ generated iron salts.…”

Interactions Between Two Cobalt Salen Centers Bridged by Non‐Conjugated Linkers**

“…The use of this and similar “privileged catalysts” [7] is not limited to oxygen transfer. Highly cis ‐ and enantio‐ or diastereoselective cyclopropanation, [10,11] cross‐coupling, [12] electroreductive alkylation of olefins, [13] epoxide ring opening, [14] aziridination, [15] carbonyl cyanosilylation, [16] or oxidative isomerization of allyl ethers to Z ‐enol ethers [17] have been reported recently, just to name a few.…”