α-Diazoacetamides in Sc(OTf)3-Catalyzed Tiffeneau–Demjanov Ring Expansion: Application towards the Synthesis of Rare Bicyclic Pyrazoles
作者:Mikhail Krasavin、Sergey Chuprun、Dmitry Dar’in、Grigory Kantin、Petr Zhmurov
DOI:10.1055/s-0039-1690047
日期:2020.3
A novel Sc(OTf)3-catalyzed Tiffeneau–Demjanov ring expansion of six-membered cyclic ketones has been developed. The resulting seven-membered cyclic β-keto carboxamides were found to be versatile precursors to rare bicyclic pyrazoles obtained in modest to good yields via condensation with aryl hydrazines in the presence of Lawesson’s reagent.
已经开发了一种新型的 Sc(OTf)3 催化的六元环酮的 Tiffeneau-Demjanov 环扩展。发现所得的七元环状 β-酮甲酰胺是稀有双环吡唑的通用前体,通过在劳森试剂的存在下与芳基肼缩合以中等至良好的产率获得。