The reaction of aliphatic ketones with aliphatic or aromatic nitriles in the presence of trifluoromethanesulfonic anhydride has been shown to be a very useful method for the preparation of alkyl- and aryl-pirimidines. The reaction shows a high degree of regioselectivity that depends on the characteristics of the residues attached at the carbonyl group. The results from different branched symmetric
Strategy for the Synthesis of Pyrimidine Derivatives: NbCl<sub>5</sub>-Mediated Cycloaddition of Alkynes and Nitriles
作者:Yasushi Satoh、Kaoru Yasuda、Yasushi Obora
DOI:10.1021/om300669s
日期:2012.8.13
Intermolecular cycloadditions of alkynes (terminal alkynes and internal alkynes) with aryl nitriles were successfully achieved, using an NbCl5 complex, to give substituted pyrimidine derivatives in high yields with excellent chemo- and regioselectivity.
FeCl<sub>3</sub>-Assisted Niobium-Catalyzed Cycloaddition of Nitriles and Alkynes: Synthesis of Alkyl- and Arylpyrimidines Based on Independent Functions of NbCl<sub>5</sub>and FeCl<sub>3</sub>Lewis Acids
作者:Maito Fuji、Yasushi Obora
DOI:10.1021/acs.orglett.7b02708
日期:2017.10.20
NbCl5-catalyzed [2 + 2 + 2] cycloaddition of nitriles with alkynes was used to synthesize pyrimidine derivatives. In this reaction, the use of individual Lewis acids, namely NbCl5 and FeCl3, is a key strategy for achieving the reaction using a catalytic amount of NbCl5. The roles of the two Lewis acids were investigated using FT-IR spectroscopy. The results showed that NbCl5 served as an efficient