The metal-free [2 + 2 + 1] annulation of alkynes, nitriles, and O-atoms for the regioselective assembly of 2,4-disubstituted and 2,4,5-trisubstituted oxazole compounds has been achieved by the use of PhIO with TfOH or Tf2NH. The present reaction could be applied to a facile synthesis of an anti-inflammatory drug.
Iodine(III)-Catalyzed Formal [2 + 2 + 1] Cycloaddition Reaction for Metal-Free Construction of Oxazoles
作者:Takuma Yagyu、Yusuke Takemoto、Akira Yoshimura、Viktor V. Zhdankin、Akio Saito
DOI:10.1021/acs.orglett.7b00742
日期:2017.5.19
The iodine(III) catalyst, in situ generated from iodoarene as a precatalyst with m-CPBA and Tf2NH, promoted the metal-free [2 + 2 + 1] cycloaddition-type reactions of alkynes, nitriles, and oxygen atoms for the regioselective formations of 2,4-disubstituted and 2,4,5-trisubstituted oxazole. A first example of iodine catalysis for multicomponent reactions is represented.
An iodine-mediated oxidative dehydrogenation of β-acylamino ketones has been developed for the synthesis of β-ketoenamides in moderate to good yields. Only Z-isomers are accessed due to the intramolecular H-bonding interaction in the HI-elimination step.
已开发出一种碘介导的 β-酰氨基酮氧化脱氢,用于以中等至良好的产率合成 β-酮烯酰胺。由于 HI 消除步骤中的分子内 H 键相互作用,只能访问 Z 异构体。
10.3998/ark.5550190.p009.965
作者:Saito, Akio
DOI:10.3998/ark.5550190.p009.965
日期:——
I<sub>2</sub>-Catalyzed C–O Bond Formation and Dehydrogenation: Facile Synthesis of Oxazolines and Oxazoles Controlled by Bases
A general method for the synthesis of oxazolines and oxazoles was developed through I-2-catalyzed C-O bond formation and dehydrogenation with the same oxidant, TBHP. By simply tuning reaction bases, either oxazolines or oxazoles were selectively produced from beta-acylamino ketones.