A photocatalytic formal [3+2] cycloaddition of 2H‐azirines with alkynes has been achieved under irradiation by visiblelight in the presence of organic dye photocatalysts. This transformation provides efficient access to highly functionalized pyrroles in good yields and has been applied to the synthesis of drug analogues. A primary trial of photocascade catalysis merging energy transfer and redox neutral
在有机染料光催化剂的存在下,在可见光照射下,已实现了2 H H叠氮基与炔烃的光催化形式[3 + 2]环加成反应。这种转化提供了以高收率高效获得高度官能化吡咯的途径,并已应用于药物类似物的合成。光级联催化合并能量转移和氧化还原中性反应的初步试验显示是成功的。
[3 + 2]-Cycloaddition of 2<i>H</i>-Azirines with Nitrosoarenes: Visible-Light-Promoted Synthesis of 2,5-Dihydro-1,2,4-oxadiazoles
A formal [3 + 2]-cycloaddition reaction of 2H-azirines with nitrosoarenes has been achieved under irradiation by visible light with the assistance of organic dye photoredox catalyst. This method utilizes nitrosoarenes as efficient radical acceptors and provides a green and powerful method for a series of biologically important 1,2,4-oxadiazole derivatives in moderate to good yields.
Ruthenium-Catalyzed C−C Bond Cleavage of 2<i>H</i>
-Azirines: A Formal [3+2+2] Cycloaddition to Fused Azepine Skeletons
作者:Tengfei Li、Fen Xu、Xincheng Li、Chunxiang Wang、Boshun Wan
DOI:10.1002/anie.201510820
日期:2016.2.18
2H‐azirines can serve as three‐atom synthons by C−C bond cleavage, however, it involves a high energy barrier under thermal conditions (>50.0 kcal mol−1). Reported is a ruthenium‐catalyzed [3+2+2] cycloaddition reaction of 2H‐azirines with diynes, thus leading to the formation of fused azepine skeletons. This approach features an unprecedented metal‐catalyzed C−C bond cleavage of 2H‐azirines at room