An Electrochemical Coupling of Organic Halide with Aldehydes, Catalytic in Chromium and Nickel Salts. The Nozaki−Hiyama−Kishi Reaction

Abstract

[reaction: see text] Electrochemical arylation of arenecarboxaldehydes using an iron sacrificial anode in the presence of chromium and nickel catalysts afforded the corresponding arylated secondary alcohols in moderate to good yields. The chromium and nickel salts as catalysts are obtained by oxidation of a stainless steel rod during a preelectrolysis in 7% and 3%, respectively. The process was also applied to the addition of vinyl halide, allyl acetate, or alpha-chloroester to aromatic aldehydes.

Mechanistic investigation of the iron-mediated electrochemical formation of β-hydroxyesters from α-haloesters and carbonyl compounds

“…This was formerly achieved in the presence of a nickel-bipyridine complex as the catalyst and a sacrificial zinc anode [15]. Then, we discovered an electrochemical method catalytic in both chromium and nickel salts using a sacrificial stainless steel or iron rod anode, which raised the question of the role of the iron salts [16]. More recently, we reported an original version of the Reformatsky reaction using FeBr 2 in the presence of 2,2 0 -bipyridine and a sacrificial iron rod anode (Scheme 1) [17].…”

Nickel Bromide Bipyridine

“…Thus, a true chromium-nickel-catalyzed NHK version of this reaction was developed to avoid this side reaction. 8 The chromium and the nickel were ingeniously introduced in the medium by a controlled preelectrolysis using a stainless steel (Fe:Cr:Ni = 72:18:10) sacrificial anode such as to provide a solution containing 7 mol % of Cr II and 3 mol % Ni II in DMF. Then, 3 mol % bipy was added as well as the two reactants (ArX and Ar CHO), before the electrolysis was run with a pure iron rod (eq 3).…”

“…12 Another NiBr 2 bipy-based reaction providing alkyl or aryl ketones relies on metal-carbonyl complexes. In this case, the Ni 0 CObipy intermediate is prepared by direct carbonylation of Ni 0 bipy using Fe(CO) 5 , Fe 3 (CO) 12 , M(CO) 6 (with M = W, Cr, or Mo) or Co 2 (CO) 8 . 13 Generated in the presence of RX, this latter provides immediately RNiCOXbipy and the rest of the mechanism is as above.…”

Carbon−Carbon Bond Formation with Electrogenerated Nickel and Palladium Complexes

“…The proposed mechanism involves an oxidative addition of the vinyl or aryl halide to an electrogenerated Pd 0 complex, followed by a transmetallation by Cr III The Cr III /(bipy)Ni II system also has been tested in the electrochemical NozakiϪHiyamaϪKishi reaction for the arylation of aldehydes using an sacrificial iron anode. [142] With the use of a stainless-steel anode containing chromium, a large variety of benzaldehyde arylations have been effected, leading to substituted arylated secondary alcohols in 50Ϫ71% yields (Scheme 28). [143] Scheme 28. a) e Ϫ , [NiBr 2 (bipy)] (10 mol %), DMF, one-compartment cell, stainless steel anode containing Fe/Cr/Ni (72:18:10)…”