first Pd-catalyzed C–H ethoxycarbonyldifluoromethylation with BrCF2CO2Et has been developed. The use of a bidentate phosphine ligand (Xantphos) is critical for the reaction to occur. A variety of electron-richheteroarenes, including indoles, furans, thiophenes, and pyrroles, can be ethoxycarbonyldifluoromethylated in moderate to excellent yields. The reactions take place at the C–H bonds adjacent to
已经开发出了第一个由BrCF 2 CO 2 Et催化的Pd催化的C–H乙氧基羰基二氟甲基化反应。双齿膦配体(Xantphos)的使用对于反应的发生至关重要。各种电子富集的杂芳烃,包括吲哚,呋喃,噻吩和吡咯,都可以以中等至极好的收率被乙氧基羰基二氟甲基化。反应发生在杂原子附近的CH键上,具有很高的区域选择性。该方法为将二氟烷基引入富电子杂芳烃提供了新的协议。
Copper-Catalyzed Direct C-2 Difluoromethylation of Furans and Benzofurans: Access to C-2 CF<sub>2</sub>H Derivatives
We report herein the first copper-catalyzed C-2 difluoromethylation of furans and benzofurans. The developed methodology allows the selective introduction of the CF2CO2Et moiety at C-2 using CuI as a catalyst. This process was applied to a broad range of furans and benzofurans, giving the functionalized products in moderate to good yields. The resulting products were then decarboxylated to afford the highly valuable C-2-CF2H-substituted furans and benzofurans in good yields.