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-acylamidoximes
作者:Hiromichi Otaka、Junya Ikeda、Daisuke Tanaka、Masanori Tobe
DOI:10.1016/j.tetlet.2013.12.016
日期:2014.1
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
氢氧化四丁基铵(TBAH)是氟化四丁基铵(TBAF)的一种高效,温和的替代品,用于由O-酰基酰胺基肟对1,2,4-恶二唑进行碱催化的环化反应。对于大多数3,5-取代的1,2,4-恶二唑,在室温下通过添加0.1当量的TBAH可以显着加速反应。该方法也更普遍地适用于允许更大范围的基板。另外,由于不存在氟化物,TBAH不会导致反应堆容器的腐蚀,因此更适合大规模合成。