Photocycloaddition of Isocoumarins and Isothiocoumarins to Alkenes
摘要:
On irradiation in the presence of tetrachloroethene (TCE), both isocoumarins 3 and isothiocoumarins 4 afford in high yields the cis-fused cycloadducts 8 and 9, while only the oxacycles 3 undergo photocycloaddition to 2,3-dimethylbut-2-ene (TME) to give mixtures of cis- and trans-fused products 10 and 11, respectively, in moderate yields. This higher efficiency in reacting with TCE as compared to TME for compounds 3 and 4 contrasts the behavior of simple cyclic enones, e.g., 5,5-dimethylcyclohex-2-enone (12), which is converted to bicyclooctanones about fifty times faster with TME than with TCE.
Rhodium‐Catalyzed Direct Vinylene Annulation of Sulfoxonium Ylides and <i>N</i>‐carbamoylindoles with Vinylene Carbonate
作者:Jia‐Lin Song、Lin Xiao、Shao‐Yong Chen、Yi‐Chuan Zheng、Yan‐Zhi Liu、Shang‐Shi Zhang、Bing Shu
DOI:10.1002/adsc.202300135
日期:2023.5.12
In this study, Rh(III)-catalyzed C−H bifunctionalization and direct vinylene annulation of sulfoxonium ylides and N-carbamoylindoles with vinylenecarbonate was accomplished, which afforded a series of naphthalenones containing a β-ketosulfoxonium ylide moiety, isocoumarins, and pyrimidones. This protocol featured mild conditions, broad substrate scope, and functional-groups compatibility. In addition