Department of Chemistry, Fudan University , 220 Handan Road, Shanghai 200433, China.
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , 345 Lingling Road, Shanghai 200032, China.
Org Lett. 2017 Sep 1;19(17):4472-4475. doi: 10.1021/acs.orglett.7b02010. Epub 2017 Aug 15.
N-Radical initiated aminosulfonylation of unactivated C(sp)-H bond through insertion of sulfur dioxide in the presence of visible light is reported. O-Aryl oximes react with DABCO·(SO) smoothly at room temperature under blue LED irradiation without any metals or photoredox catalysts, generating diverse 5,6-dihydro-4H-1,2-thiazine 1,1-dioxides in good yield. Additionally, this approach can be extended to the synthesis of 1H-benzo[d][1,2]thiazine 2,2-dioxides. During the reaction process, an N-radical is initiated by the treatment of O-aryl oximes with DABCO·(SO) under visible-light irradiation. It is followed by aminosulfonylation of a nearby C(sp)-H bond through 1,5-hydrogen atom transfer with accompanying insertion of sulfur dioxide to provide 1,2-thiazine 1,1-dioxide derivatives.
本文报道了在可见光照射下，通过二氧化硫的插入，N-自由基引发未活化的 C(sp)-H 键的氨基磺酰化反应。在室温下，DABCO·(SO)与邻芳基肟在蓝光 LED 照射下无需任何金属或光氧化还原催化剂即可顺利反应，以良好的收率生成多种 5,6-二氢-4H-1,2-噻嗪 1,1-二氧化物。此外，该方法可扩展至 1H-苯并[d][1,2]噻嗪 2,2-二氧化物的合成。在反应过程中，O-芳基肟与 DABCO·(SO)在可见光照射下处理，引发 N-自由基。随后通过 1,5-氢原子转移对附近的 C(sp)-H 键进行氨基磺酰化，同时插入二氧化硫，提供 1,2-噻嗪 1,1-二氧化物衍生物。
