Efficient synthesis of 1,2-bis(alkoxycarbonyl)pyrazol-3-ones from 2,3-allenoic acids, azodicarboxylates and PPh3
作者:Ruizhi Lü、Xin Cheng、Xingliang Zheng、Shengming Ma
DOI:10.1039/c3cc48215d
日期:——
An efficient cascade reaction of 2,3-allenoic acids with dialkylazodicarboxylate in the presence of PPh3 affording 1,2-bis(alkoxycarbonyl)pyrazol-3-ones in moderate yields has been developed. The reaction may proceed via the intramolecular Michael addition of the expected 2,3-allenoyl hydrazines.