CSIR-National Chemical Laboratory, Division of Organic Chemistry, Dr. Homi Bhabha Road, Pune - 411008, India.
Org Biomol Chem. 2018 Jan 24;16(4):536-540. doi: 10.1039/c7ob02977b.
An eosin Y photoredox catalyzed net redox neutral process for 3-sulfonylindoles via the anionic oxidation of sodium sulfinate salts and its radical cascade cyclization with 2-alkynyl-azidoarenes was developed with visible light as a mediator. The reaction offers metal and oxidant/reductant free, visible light mediated vicinal sulfonamination of alkynes to 2-aryl/alkyl-3-sulfonylindoles and proceeds via the generation of a sulfur-centered radical through direct oxidation of the sulfinate anion by an excited photocatalyst with a reductive quenching cycle. The mild conditions, use of an organic dye as photo-catalyst, bench stability and easily accessible starting materials make the present approach green and attractive.
发展了一种曙红 Y 光氧化还原催化的、通过亚硫酸钠盐阴离子氧化和与 2-炔基叠氮芳烃的自由基级联环化的、净氧化还原中性过程，可将 3-磺酰基吲哚转化为 2-芳基/烷基-3-磺酰基吲哚。该反应提供了金属和氧化剂/还原剂免费、可见光介导的炔烃邻位磺酰胺化，通过激发光催化剂直接氧化亚磺酸盐阴离子生成硫中心自由基，同时进行还原猝灭循环。温和的条件、使用有机染料作为光催化剂、在实验台上的稳定性和容易获得的起始材料使本方法具有绿色和吸引力。
