Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Department of Chemistry, Northeast Normal University, Changchun 130024, China.
State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China.
Org Lett. 2020 Mar 6;22(5):2012-2016. doi: 10.1021/acs.orglett.0c00395. Epub 2020 Feb 19.
A transition-metal-free [3 + 2] cycloaddition between trifluoroacetaldehyde -triftosylhydrazone (TFHZ-Tfs) and alkynes is reported. This protocol provides an operationally simple and general method for the synthesis of diverse 3-trifluoromethylpyrazoles in good to excellent yields with broad substrate scope, including aryl, heteroaryl, and alkyl terminal alkynes, and electron-deficient internal alkynes. The synthetic potential of this method was further demonstrated by the synthesis of an antiarthritic drug Celecoxib in multigram scale.
报道了三氟乙酰基-triftosylhydrazone（TFHZ-Tfs）和炔烃之间的无过渡金属[3+2]环加成反应。该方案提供了一种操作简单、通用的方法，可在良好到优异的收率范围内合成多种 3-三氟甲基吡唑，底物范围广泛，包括芳基、杂芳基和烷基末端炔烃以及缺电子的内部炔烃。该方法的合成潜力通过在多克规模下合成抗关节炎药物塞来昔布进一步证明。
