Yunusova SN, Novikov AS, Soldatova NS, Vovk MA, Bolotin DS. Iodonium salts as efficient iodine(iii)-based noncovalent organocatalysts for Knorr-type reactions.
RSC Adv 2021;
11:4574-4583. [PMID:
35424399 PMCID:
PMC8694507 DOI:
10.1039/d0ra09640g]
[Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 01/05/2021] [Indexed: 12/11/2022] Open
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.
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