Copper-catalyzed cyclization of Z-oximes into 3-methyl-1,2-benzisoxazoles
摘要:
A practical and effective room temperature copper-catalyzed cyclization of Z-oximes is developed. 3-Methyl-1,2-benzisoxazoles are obtained in 58-79% yields, Also, the Z-selective synthesis of o-bromo acetophenone oximes is presented for the first time. (C) 2009 Elsevier Ltd. All rights reserved.
A practical and effective Z-selective synthesis of o-bromoacetophenone N-tosylhydrazones is developed. Subsequent cyclization of Z-tosylhydrazones to furnish 3-methylindazoles is accomplished with the aid of copper and DMEDA in aqueous ethanol. Cyclization reactions are complete at ambient temperature in 10 min to afford the desired compounds in excellent yields.
Total Synthesis of (±)-8-Oxo-erythrinine, (±)-8-Oxo-erythraline, and (±)-Clivonine
作者:Maomao He、Chunrong Qu、Bingbing Ding、Hao Chen、Yangyan Li、Guofu Qiu、Xianming Hu、Xuechuan Hong
DOI:10.1002/ejoc.201500265
日期:2015.5
Total syntheses of the erythrina alkaloids (±)-8-oxo-erythrinine and (±)-8-oxo-erythraline have been developed, based on a substrate-controlled intramolecular 6-exo-trig selective radical spirocyclization that establishes the quaternary center of the B-rings. An improved totalsynthesis of (±)-clivonine has also been reported, based on an intramolecular 6-endo-trig free-radical cyclization of a highly
A practical and environmentally friendly synthesis of 3-aminomethyl-N-tosyl-indazoles is developed. The in situ formed vinyl azines are reacted with amines to furnish amino functionalized anti-hydrazones in excellent yields. Subsequent copper-catalyzed cyclization at ambient temperature is effective and desired compounds are obtained in short reaction times. Also, the formation of bisindazoles is presented for the first time. (C) 2010 Elsevier Ltd. All rights reserved.