Beilstein J. Org. Chem.2022,18, 1040–1046, doi:10.3762/bjoc.18.105
necessary in some cases (path b in Scheme 1) [14][15]. On the other hand, N-acyliminium ions can easily be generated by electrochemical oxidation without those reagents. Electrochemical oxidation of amides/carbamates yielding N-acyliminium ions is well known as Shonooxidation (path c in Scheme 1) [16] and
-rich arenes or silyl enol ethers preferentially takes place at the anode due to their, in general, more positive oxidation potentials than those of amides/carbamates. Therefore, Friedel–Crafts-type amidomethylation by using Shonooxidation is successfully carried out as a two-step process
: electrochemical oxidation of amides/carbamates yielding α-methoxylated amides/carbamates (Shonooxidation, path c in Scheme 1) followed by the reaction of the isolated α-methoxylated amides/carbamates with arenes in the presence of a Lewis acid catalyst (path e in Scheme 1) [16]. Although the use of CH2Cl2 as a
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Graphical Abstract
Scheme 1:
Generation of N-acyliminium ion: previous and present works.
Beilstein J. Org. Chem.2014,10, 3056–3072, doi:10.3762/bjoc.10.323
are useful reactive synthetic intermediates in a variety of important carbon–carbon bond forming and cyclisation strategies in organic chemistry. The advent of an electrochemical anodic oxidation of unfunctionalised amides, more commonly known as the Shonooxidation, has provided a complementary route
radical initiating agent such as distannane (Scheme 6). This allows the N-acyliminium ion to react with an alkyl halide to generate the typical carbon–carbon products of the Shonooxidation [19][27][28] Examples of reactions with activated olefins have been reported using the generation of carbon free
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Graphical Abstract
Scheme 1:
Application of anodic oxidation to the generation of new carbon-carbon bonds [11].