Cycloaddition of Trifluoroacetaldehyde <i>N</i>-Triftosylhydrazone (TFHZ-Tfs) with Alkynes for Synthesizing 3-Trifluoromethylpyrazoles
作者:Hongwei Wang、Yongquan Ning、Yue Sun、Paramasivam Sivaguru、Xihe Bi
DOI:10.1021/acs.orglett.0c00395
日期:2020.3.6
(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 terminalalkynes, and electron-deficient internalalkynes. The synthetic potential of this method was further demonstrated by the synthesis of an antiarthritic
Coupling of Trifluoroacetaldehyde <i>N</i>-Triftosylhydrazone with Organoboronic Acids for the Synthesis of <i>gem</i>-Difluoroalkenes
作者:Yu Ma、Bhoomireddy Rajendra Prasad Reddy、Xihe Bi
DOI:10.1021/acs.orglett.9b03740
日期:2019.12.20
synthesis of alkyl gem-difluoroalkenes remains a difficult task in organic synthesis. Here, we report a general and efficient approach for tackling this problem by gem-difluoroolefination of trifluoroacetaldehyde N-triftosylhydrazone with organoboronic acids. This protocol is operationally simple, free of transition metals, and suitable for a broad range of organoboronic acids. Moreover, the utility
Lewis Base‐Catalyzed Cycloaddition of Heterocyclic Alkenes with 2,2,2‐Trifluorodiazoethane (CF
<sub>3</sub>
CHN
<sub>2</sub>
): Access to Trifluoromethylated Pyrazolines and Pyrazoles
作者:Tingting Cao、Zhen Yang、Yunfang Sun、Nannan Zhao、Shan Lu、Jing Zhang、Lei Wang
DOI:10.1002/ejoc.202100521
日期:2021.6.7
An efficient Lewis base catalytic protocol to biologically important trifluoromethylated pyrazolines and pyrazoles is developed through [3+2] triazene-heterocycilc alkene cycloaddition reactions of an array of oxa-/aza-benzonorbornadienes and coumarins with CF3CHN2. This approach features good functional group tolerance and scaffold diversity. Synthetic utility of the protocol is highlighted by late-stage
Metal-free [2 + 1 + 3] Cycloaddition of Trifluoroacetaldehyde <i>N</i>-Sulfonylhydrazones with Hexahydro-1,3,5-triazines Leading to Trifluoromethylated 2,3,4,5-Tetrahydro-1,2,4-triazines
作者:Zhongxue Fang、Qihao Jin、Xinyu Wang、Yongquan Ning
DOI:10.1021/acs.joc.1c02810
日期:2022.3.4
A transition-metal-free [2 + 1 + 3] cycloaddition of trifluoroacetaldehyde N-sulfonylhydrazone and hexahydro-1,3,5-triazine was described. This operationally simple protocol provides a general synthesis of diverse trifluoromethylated 2,3,4,5-tetrahydro-1,2,4-triazines in 81–97% yield with a broad substrate scope, including aryl, benzyl, and alkyl hexahydro-1,3,5-triazine.