37649-20-0Relevant articles and documents
Catalytic aza-wittig reaction of acid anhydride for the synthesis of 4H-benzo[d][1,3]oxazin-4-ones and 4-benzylidene-2-aryloxazol-5(4H)-ones
Wang, Long,Xie, Yi-Bi,Huang, Nian-Yu,Yan, Jia-Ying,Hu, Wei-Min,Liu, Ming-Guo,Ding, Ming-Wu
, p. 4010 - 4016 (2016/07/06)
Compared to the aza-Wittig reaction of aldehydes, ketones, amides, and esters, the aza-Wittig reaction of acid anhydride was always overlooked, which should be an important part of Wittig reactions. Here, the aza-Wittig reaction of anhydride and catalytic aza-Wittig reaction of anhydride were both developed with high yields, which provides an efficient method to synthesize of 4H-benzo[d][1,3]oxazin-4-ones and 4-benzylidene-2-aryloxazol-5(4H)-ones. The strategy of copper-catalyzed reduction of phosphine oxide was used and found effective for this transformation. Additionally, the one-pot catalytic aza-Wittig reaction of carboxylic acids was achieved. Furthermore, NMR experiments and Hammett plot recorded the process of catalytic aza-Wittig reaction of anhydride, which provides direct proof that the copper-catalyzed reduction of waste phosphine oxide is the key step in this transformation.
