Base-mediated formal [3+2] cycloaddition of β,γ-alkenyl esters and p-TsN3 for the synthesis of pyrazoles

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2017,（7）
• 页码范围: 493-496
• 页数: 4页
• 语种: 英文

摘要

A novel 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-mediated formal cycloaddition of β,γ-alkenyl esters with p-tolylsulfonylazide (p-TsN3) for the synthesis of 3,5-disubstituted pyrazoles has been developed.The reaction proceeded through diazotization of β,γ-alkenyl esters sequential with thermodynamic cyclization.p-Tolylsulfonylazide played a role as a source of two-nitrogen synthons.The reaction employs readily available starting materials,tolerates a wide range of functional groups,and proceeds under mild conditions.