Categories: C-N Bond Formation >
Synthesis of Hydrazones
Tosyl- and Boc-hydrazones were found to be effective nucleophiles in the Mitsunobu reaction. Tosyl hydrazones reacted cleanly with primary and secondary alcohols when co-administered to a cooled DBAD/PPh3 or DEAD/PPh3 complex.
J. M. Keith, L. Gomez, J. Org. Chem., 2006, 71, 7113-7116.
Central to an alternative source of substrates for Fischer indolizations was a palladium-catalyzed coupling to prepare N-aryl benzophenone hydrazones. Hydrolysis of the hydrazones in the presence of ketones produced enolizable hydrazones that underwent Fischer indolization.
S. Wagaw, B. H. Yang, S. L. Buchwald, J. Am. Chem. Soc., 1998, 120, 6621-6622.
A metal-free photocatalytic coupling reaction of α-diazoacetates and alkyl N-hydroxyphthalimide esters provides structurally and functionally diverse N-alkyl hydrazones. By employing Rose Bengal as a photocatalyst with yellow LEDs irradiation and Hantzsch ester as both an electron donor and proton source, over 60 N-alkyl hydrazones were synthesized.
C.-M. Chan, Q. Xing, Y.-C. Chow, S.-F. Hung, W.-Y. Yu, Org. Lett., 2019, 21, 8037-8043.
A general two-step synthesis of substituted 3-aminoindazoles from 2-bromobenzonitriles involves a palladium-catalyzed arylation of benzophenone hydrazone followed by an acidic deprotection/cyclization sequence. This procedure offers a general and efficient alternative to the typical SNAr reaction of hydrazine with o-fluorobenzonitriles.
V. Lefebvre, T. Cailly, F. Fabis, S. Rault, J. Org. Chem., 2010, 75, 2730-2732.
A highly chemo- and regioselective allylic amination of various hydrazones and hydrazides with allylic carbonates proceeds at ambient temperature in the presence of an [Ir(COD)Cl]2/pyridine catalyst, ammonium iodide, and diethylzinc to afford the corresponding N-allylation products in high yields.
R. Matunas, A. J. Lai, C. Lee, Tetrahedron, 2005, 61, 6298-9308.