Copper-Catalyzed Direct Ortho-Alkylation of N-Iminopyridinium Ylides with N-Tosylhydrazones

Abstract

Copper-catalyzed cross-coupling of N-tosylhydrazones with N-iminopyridinium ylides leads to the direct C-H alkylation. This direct C-H bond alkylation transformation uses inexpensive CuI as the catalyst without any ligand. The reaction is operationally simple and conducted under mild conditions, giving the corresponding alkylated pyridines in moderate to good yields. DFT calculation provides insights into the reaction mechanism, suggesting that the reaction proceeds through the Cu carbene migratory insertion process.

Efficient access to β-vinylporphyrin derivatives via palladium cross coupling of β-bromoporphyrins with N-tosylhydrazones

“…Both substrates were prepared by following literature procedures; the halide partner by controlled bromination of 5,10,15,20-tetraphenylporphyrin (TPP) with N -bromosuccinimide followed by metallation with Zn(AcO) 2 [31–32] and the tosylhydrazones 2a–c by reaction of the adequate ketones with tosylhydrazines [33]. The use of the porphyrin zinc complex avoids the complexation of the tetrapyrrolic macrocycle with Pd(II) formed during the catalytic cycle, and in this way prevents the loss of the catalyst.…”

Copper‐Catalyzed Direct Cross‐Coupling of Compounds Containing Activated C–H/Heteroatom–H Bonds with N‐Tosylhydrazones

“…[36] The sole purpose of the N-iminobenzoyl system was to provide control over regioselectivity. The hydrazones were investigated further.…”

N‐Imide Ylide‐Based Reactions: CH Functionalization, Nucleophilic Addition and Cycloaddition

“…Wang and co-workers discovered the direct ortho-alkylation of N-iminopyridinium ylide 16 when N-tosylhydrazone 22 was employed as the substrate in the presence of CuI. [17] DFT calculations suggested a copper carbene migratory insertion process.…”