可见光促进的双键三氟甲基化反应研究(英文)

Visible-Light Induced Trifluoromethylation of Internal Olefinic C—H Bonds through Photoredox Catalysis

报道了一种可见光促进的双键直接三氟甲基化的方法.研究中利用Ru(bpy)3Cl2为催化剂,Togni’s试剂为三氟甲基来源,在可见光促进下实现了含羰基烯烃的三氟甲基化.该反应具有方法简便,条件温和,可以获得较高的反应收率,同时避免了有毒试剂的使用.

An approach for direct trifluoromethylation of internal olefins of α-oxoketene dithioacetals has been achieved by using Ru（bpy）_3Cl_2 as photocatalyst and Togni＇s reagent as trifluoromethylating agent under irradiation with visible light. Under a nitrogen atmosphere, a mixture of α-oxoketene dithioacetal（0.1 mmol）, Togni＇s reagent（0.15 mmol）, Ru（bpy）_3Cl_2（0.005 mmol）, and Na_2CO_3（0.3 mmol） in DMSO（1 m L） was stirred at room temperature for 72 h under 5 W Blue LEDS, which led to the trifluoromethylated products in 40%~90% yield. This protocol provides an efficient and easy access to prepare trifluoromethylated dithioalkyl α-oxoketene acetals under mild conditions, and is highlighted by its operational simplicity and avoiding using toxic reagent. Furthermore, the gram-scale reaction of 1a suggested the potential application of this protocol in organic synthesis.