Tetrahedron Letters

Construction of 3, 5-substituted 1, 2, 4-oxadiazole rings triggered by tetrabutylammonium hydroxide: a highly efficient and fluoride-free ring closure reaction of O- …

H Otaka, J Ikeda, D Tanaka, M Tobe

Index: Otaka, Hiromichi; Ikeda, Junya; Tanaka, Daisuke; Tobe, Masanori Tetrahedron Letters, 2014 , vol. 55, # 5 p. 979 - 981

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Citation Number: 3

Abstract

Abstract Tetrabutylammonium hydroxide (TBAH) is an efficient and mild alternative to tetrabutylammonium fluoride (TBAF) for base catalyzed cyclizations of 1, 2, 4-oxadiazoles from O-acylamidoximes. For most 3, 5-substituted 1, 2, 4-oxadiazoles the reactions were dramatically accelerated by addition of 0.1 equiv of TBAH at room temperature. This method was also more generally applicable allowing for a wider range of substrates. Additionally, ...