Synthesis of Chiral Pyrazoles: A 1,3-Dipolar Cycloaddition/[1,5] Sigmatropic Rearrangement with Stereoretentive Migration of a Stereogenic Group
作者:M. Carmen Pérez-Aguilar、Carlos Valdés
DOI:10.1002/anie.201506881
日期:2015.11.9
the obtention of chiral pyrazoles with a stereogenic group directly attached at a nitrogen atom. The cascade reaction includes decomposition of the hydrazone into a diazocompound, 1,3‐dipolar cycloaddition of the diazo compound with the alkyne, and [1,5] sigmatropic rearrangement with migration of the stereogenic group. This strategy has been successfully applied to the synthesis of structurally diverse
末端炔烃与α-手性甲苯磺酰hydr之间的反应会导致获得手性吡唑,而手性吡唑具有直接与氮原子相连的立体异构基团。级联反应包括分解为重氮化合物,重氮化合物与炔烃的1,3-偶极环加成以及随着立体异构基团的迁移而发生的[1,5]σ重排。通过从α-苯基丙酸,α-氨基酸和2-甲氧基环己酮获得的α-手性甲苯磺酰nes,该策略已成功应用于合成结构多样的手性吡唑。值得注意的是,[1,5]σ重排的立体保留代表了这种立体特异性转换的非常罕见的例子。