Carbon–oxygen single bonds are ubiquitous in natural products whereas efficient methods for their reductive defunctionalization are rare. In this work an environmentally benign protocol for the activation of carbon–oxygen single bonds of alcohols towards a reductive bond cleavage under visible light photocatalysis was developed. Alcohols were activated as 3,5-bis(trifluoromethyl)-substituted benzoates and irradiation with blue light in the presence of [Ir(ppy)2(dtb-bpy)](PF6) as visible light photocatalyst and Hünig’s base as sacrificial electron donor in an acetonitrile/water mixture generally gave good to excellent yields of the desired defunctionalized compounds. Functional group tolerance is high but the protocol developed is limited to benzylic, α-carbonyl, and α-cyanoalcohols; with other alcohols a slow partial C–F bond reduction in the 3,5-bis(trifluoromethyl)benzoate moiety occurs.
碳-氧单键在天然产物中普遍存在,而用于其还原脱官能团化的有效方法却很少见。在这项工作中,开发了一种对醇的碳-氧单键进行环境友好的激活,以实现在可见光光催化下的还原键裂解的方法。醇被激活为3,5-双(三氟甲基)取代苯甲酸酯,通过在蓝光照射下,在存在[Ir(ppy)₂(dtb-bpy)](PF₆)作为可见光光催化剂和Hünig's碱作为牺牲电子供体的乙腈/水混合物中,通常可以获得所需的脱官能化化合物的良好至优异产率。对官能团的耐受性很高,但所开发的方法仅限于苄基、α-羰基和α-氰基醇;对于其他醇,3,5-双(三氟甲基)苯甲酸酯中的部分C-F键还原会发生缓慢。