Beilstein J. Org. Chem.2021,17, 2505–2510, doi:10.3762/bjoc.17.167
(sp3)–H allylic alkylation of 2-alkylpyridines with Morita–Baylis–Hillman (MBH) carbonates is described. A plausible mechanism of the reaction might involve a tandem SN2’ type nucleophilic substitution followed by an aza-Coperearrangement. Various alkyl substituents on 2-alkylpyridines were tolerated
in the reaction to give the allylation products in 26–91% yields. The developed method provides a straightforward and operational simple strategy for the allylic functionalization of 2-alkypyridine derivatives.
Keywords: 2-alkylpyridines; allylic alkylation; aza-Coperearrangement; catalyst-free
MBH-derived allyl bromides (Scheme 1d) [30]. This reaction was assumed to involve the deprotonation of the initially formed 2-methylpyridinium salt by base to generate an N-allyl enamine intermediate, which undergoes a 3-aza-Coperearrangement to give the allyl-substituted products. To the best of our
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Graphical Abstract
Scheme 1:
The benzylic C(sp3)–H allylic alkylation reactions of 2-alkylpyridines.
Beilstein J. Org. Chem.2014,10, 2230–2234, doi:10.3762/bjoc.10.231
-Coperearrangement of N-galactosyl-N-homoallylamines [18]. Aminooctoses, on the other hand, are present in the aminoglycoside antibiotic apramycin [19], in the form of an aminooctodiose derivative. However, only few syntheses of this dipyranoid aminosugar [20][21] were reported so far. Thus, we were
Kirschenlohr [16] for the synthesis of aminohexoses, proved to be straightforward, albeit the reproducibility and yield usually suffered from the formation of multiple side products [17]. Another interesting approach for the synthesis of higher aminosugars, published by Kunz and Deloisy, consists of an aza
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Graphical Abstract
Scheme 1:
Functionalization of carbohydrates; reagents and conditions: (a) In, allyl bromide, EtOH/H2O, ultra...