光镍协同催化丝氨酸O-芳基化

Metallaphotoredox⁃Catalyzed O⁃Arylation of Serine

发展了光/镍协同催化丝氨酸O-芳基化,实现多种丝氨酸衍生物的芳醚快速合成反应。在乙二醇二甲醚溴化镍(NiBr_(2)(dme))/4,4'-二甲氧基-2,2'-联吡啶催化体系以及铱、光催化的协同作用下,镍催化插入碳-溴键,与丝氨酸的羟基发生转金属过程,所得Ni(II)物种被激化态Ir(Ⅲ)-物种氧化成Ni(Ⅲ)中间体,此中间体不稳定被迅速还原消除,以39%~65%的产率得到O-芳基化丝氨酸衍生物。该方法利用光致氧化还原催化,反应条件温和、高效、清洁且底物普适性较好,为具有药用价值的丝氨酸芳基醚类化合物的合成提供了新途径。

A metallaphotoredox catalyzed hydroxyl aromatization of serine is developed to achieve rapid synthesis of aryl ethers of various serine derivatives.Under the catalytic system of ethylene glycol dimethyl ether nickel bromide(NiBr_(2)(dme))/4,4'-dimethoxy-2,2'-bipyridine/zinc powder and synergistic iridium photoredox catalysis,nickel is catalyzed and inserted into the C—Br bond,and then followed by transmetalation with the hydroxyl group of serine.The resulting Ni(Ⅱ)species are oxidized by the excited Ir(Ⅲ)species to a Ni(Ⅲ)intermediate.This intermediate is unstable and reductive elimination takes place rapidly to give the target product O-arylated serine in the yields from 65%to 39%.Through a metallaphotoredox catalysis strategy,the reaction features mild,efficient,clean and broad scope of substrate,providing a new way for the synthesis of various serine derivatives with medicinal value.