Beilstein J. Org. Chem.2025,21, 630–638, doi:10.3762/bjoc.21.50
10.3762/bjoc.21.50 Abstract The electrochemical synthesis of 2-aminoprolines based on anodicdecarboxylation–intramolecular amidation of readily available N-acetylamino malonic acid monoesters is reported. The decarboxylative amidation under Hofer–Moest reaction conditions proceeds in an undivided cell
tetrahydropyran-containing amino acid derivatives via anodicdecarboxylation of N-acetylamino malonic acid monoesters to generate a stabilized carbocation (Hofer–Moest conditions), which were then reacted with a tethered oxygen nucleophile [4]. In this follow-up study, we demonstrate that N-protected amines are
in three steps (62% overall yield) from commercially available diethyl acetamidomalonate by an alkylation/hydrolysis/Boc-cleavage sequence (Scheme 1).
The development of decarboxylative amidation commenced by examining the published conditions for anodicdecarboxylation/etherification [4
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Graphical Abstract
Figure 1:
Selected examples of α,α-disubstituted cyclic amino acids in drug design.
Beilstein J. Org. Chem.2017,13, 33–42, doi:10.3762/bjoc.13.5
anodicdecarboxylation of five malonic acid derivatives. These were prepared from benzyl malonates and four menthol auxiliaries. Coelectrolyses with 3,3-dimethylbutanoic acid in methanol at platinum electrodes in an undivided cell afforded hetero-coupling products in 22–69% yield with a
.
Keywords: anodicdecarboxylation; diastereoselectivity; Kolbe electrolysis; radical hetero-coupling; radical homo-coupling; Introduction
Intermolecular radical additions with high diastereoselectivity have been described for a number of cases [1][2][3][4][5][6][7][8][9]. There are much fewer reports on
], and in intermolecular coupling of radicals generated by anodicdecarboxylation of carboxylic acids [15][16].
At the anode radicals can be generated by anodicdecarboxylation of carboxylic acids in molar quantities, in a simple procedure, unaffected by cage effects and in large diversity. For that
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Graphical Abstract
Figure 1:
Menthol auxiliaries 1–4 used in the following anodic coupling reactions.