Simovic Dragan, Di Mingping, Marks Vered, Chatfield David C, Rein Kathleen S
Department of Chemistry, Florida International University, Miami, Florida 33199, USA.
J Org Chem. 2007 Jan 19;72(2):650-3. doi: 10.1021/jo061838t.
The 1,3-dipolar cycloaddition of trimethylsilyldiazomethane with alpha,beta-unsaturated esters was examined. The resulting 1-pyrazolines isomerize to regioisomeric 2-pyrazolines (a or b) or undergo desilylation (c). Acrylates yield only b or c. beta-Substituted dipolarophiles may yield all three types of products. This work demonstrates that the distribution of 2-pyrazoline products is highly dependent on the relative configuration of the substituents on the 1-pyrazoline intermediate.
研究了三甲基硅基重氮甲烷与α,β-不饱和酯的1,3-偶极环加成反应。生成的1-吡唑啉异构化为区域异构体2-吡唑啉（a或b）或发生脱硅反应（c）。丙烯酸酯仅生成b或c。β-取代的亲偶极体可能生成所有三种类型的产物。这项工作表明，2-吡唑啉产物的分布高度依赖于1-吡唑啉中间体上取代基的相对构型。
