A cesium carbonate promoted, transition metal and halogen‐free 5‐exo‐dig type cyclization reaction for the synthesis of oxazoles and imidazoles has been developed.
Alkynyl Thioethers in Gold-Catalyzed Annulations To Form Oxazoles
作者:Raju Jannapu Reddy、Matthew P. Ball-Jones、Paul W. Davies
DOI:10.1002/anie.201706850
日期:2017.10.16
regioselective, and convergent access to densely functionalized oxazoles is realized in a functional-group tolerant manner using alkynylthioethers. Sulfur-terminated alkynes provide access to reactivity previously requiring strong donor-substituted alkynes such as ynamides. Sulfur does not act in an analogous donor fashion in this gold-catalyzed reaction, thus leading to complementary regioselective outcomes
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.
Efficient synthesis of multi-substituted oxazoles under solvent-free microwave irradiation
作者:Jong Chan Lee、Hyun Jung Choi、Yong Chan Lee
DOI:10.1016/s0040-4039(02)02493-0
日期:2003.1
A new and efficient method for the synthesis of multi-substituted oxazoles from various carbonyl compounds has been developed using sequential treatment of carbonyl compounds with HDNIB and amides such as acetamide or benzamide under solvent-free microwaveirradiation conditions.
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.