Iodonium salts as efficient iodine(iii)-based noncovalent organocatalysts for Knorr-type reactions
Sevilya N Yunusova1, Alexander S Novikov1, Natalia S Soldatova1
1Institute of Chemistry, Saint Petersburg State University Universitetskaya Nab. 7/9 Saint Petersburg 199034 Russian Federation d.s.bolotin@spbu.ru.
Abstract:
Hypervalent iodine(iii)-derivatives display higher catalytic activity than other aliphatic and aromatic iodine(i)- or bromine(i)-containing substrates for a Knorr-type reaction of N-acetyl hydrazides with acetyl acetone to give N-acyl pyrazoles. The highest activity was observed for dibenziodolium triflate, for which 10 mol% resulted in the generation of N-acyl pyrazole from acyl hydrazide and acetyl acetone typically at 50 °C for 3.5-6 h with up to 99% isolated yields. 1H NMR titration data and DFT calculations indicate that the catalytic activity of the iodine(iii) is caused by the binding with a ketone.
Related Concept Videos
Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo,...
Aldol Condensation with β-Diesters: Knoevenagel Condensation
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Overview
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by...
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene


