Main observation and conclusion
Herein, we report an efficient, tunable system for electrochemical reduction of ketones and phthalimides at room temperature without the need for stoichiometric external reductants. By utilizing NaN3 as the electrolyte and graphite felt as both the cathode and the anode, we were able to selectively reduce the carbonyl groups of the substrates to alcohols, pinacols, or methylene groups by judiciously choosing the solvent and an acidic additive. The reaction conditions were compatible with a diverse array of functional groups, and phthalimides could undergo one‐pot reductive cyclization to afford products with indolizidine scaffolds. Mechanistic studies showed that the reactions involved electron, proton, and hydrogen atom transfers. Importantly, an N3/HN3 cycle operated as a hydrogen atom shuttle, which was critical for reduction of the carbonyl groups to methylene groups.
We report here a strategy for inert C−C bond functionalization. Site-specific cleavage and functionalization of a saturated C(sp 3 )−C(sp 3 ) bond via a visible-light-induced radical process have been achieved. The general features of this reaction are as follows. (1) Both linear and cyclic C(sp 3 )−C(sp 3 ) bonds with a vicinal arene can be specifically functionalized. (2) One carbon is converted into a ketone, and another can be tunably converted into nitrile, peroxide, or halide. (3) The typical conditions include 1.0 mol % of Ru(bpy) 3 Cl 2 , 1.0 or 5.0 equiv of Zhdankin reagent, white CFL (24 W), open flask, and room temperature. These reactions offer powerful tools to modify carbon skeletons that are intractable by conventional methods. Good selectivity and functional group tolerance, together with mild and open air conditions, make these transformations valuable and attractive.
A site-specific oxidation of (sp3)C–C(sp3) and (sp3)C–H
bonds in aryl alkanes by
the use of NaNO2/HCl was explored. The method is chemical-oxidant-free,
transition-metal-free, uses water as the solvent, and proceeds under
mild conditions, making it valuable and attractive to synthetic organic
chemistry.
A direct and site-specific alkylation
of (sp3)C–H
bond with aliphatic boronic acid was achieved. By simply heating glycinates
and amines together with alkylboronic acids under an oxygen atmosphere,
a variety of unnatural α-amino acids and peptides could be obtained
in good yields.
An electrochemistry-promoted oxidative
cleavage of (sp3)C–C(sp3)/H bonds in
alkylarenes was developed.
Various aryl alkanes can be smoothly converted into ketones/aldehydes
under aerobic conditions using a user-friendly undivided cell setup.
The features of air as oxidant, scalability, and mild conditions make
them attractive in synthetic organic chemistry.
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