Selective O-Difluoromethylation of 1,3-Diones by Bromodifluoromethylating Reagents
摘要:
The regioselective Odifluoromethylation of 1,3-diones was achieved via in situ generation of difluorocarbene from bromodifluoromethylating reagents in the presence of an organic base. A wide variety of difluormethyl enol ethers were obtained in good to excellent yields. The reaction mechanism is discussed based on ab initio calculations (kcal/mol).
O-Difluoromethylation of 1,3-diones with S-difluoromethyl sulfonium salt
作者:Chun-Bo Yue、Jin-Hong Lin、Ji Cai、Cheng-Pan Zhang、Gang Zhao、Ji-Chang Xiao、HengFeng Li
DOI:10.1039/c6ra06338a
日期:——
The O-difluoromethylation of 1,3-diones with S-difluoromethyl sulfonium salt is described. The sulfonium salt was previously believed to be a direct difluoromethylation reagent, but our mechanistic investigation reveals that the O-difluoromethylation reaction proceeds not only via the direct transfer of the CF2H group, but also via a difluorocarbene process. This work represents the first protocol
The base-free O-difluoromethylation of 1,3-diones with difluorocarbene generated from difluoromethylene phosphobetaine (Ph3P+CF2CO2−) is described. The convenient reactions proceeded smoothly to give difluoromethyl enol ethers in moderate to good yields.
游离碱- O-的二氟亚甲基从生成磷酸酯1,3-二酮与二氟卡宾二氟甲基(PH 3 P + CF 2 CO 2 - )进行说明。方便的反应顺利进行,以中等至良好的产率得到二氟甲基烯醇醚。
A new method for the synthesis of difluoromethyl enol ethers by O-difluoromethylation of 1,3-diones with ClCF<sub>2</sub>CO<sub>2</sub>Et
作者:Xiaoxi Lin、Zhiqiang Weng
DOI:10.1039/c5ob00020c
日期:——
single-step protocol for the synthesis of difluoromethyl enol ether derivatives by O-difluoromethylation of 1,3-diones via in situ generation of difluorocarbene from ClCF2CO2Et has been developed. The functional group tolerance, scalability of the reaction, and mild reaction conditions make it an attractive protocol for the synthesis of biologically relevant difluoromethyl ethers of interest to the pharmaceutical