Metal-free oxidative decarbonylative alkylation of chromones using aliphatic aldehydes
作者:Rongzhen Chen、Jin-Tao Yu、Jiang Cheng
DOI:10.1039/c8ob00720a
日期:——
A decarbonylative alkylation of chromones via radical conjugate addition under metal-free conditions was developed using aliphaticaldehydes as alkylating reagents. A series of 2-tertiary, secondary, and even primary alkylated chromanones were obtained in moderate to excellent yields.
A metal-free site-specific C2-hydroxyalkylation of chromones through the Minisci-type reaction using simple alcohols was developed. This transformation proceeds via radical sp3 C–H activation and subsequent conjugateaddition, generating a series of C2-hydroxyalkylated chromanones in moderate to good yields. Besides, ethers were also compatible in this Minisci reaction, leading to corresponding C2
The selective preparation of 5‐alkylated and 5‐alkenylated chromones from readily accessible substrates using Rh(III) and Ru(II) catalysts has been successfully developed. Forty‐one examples of the target compounds were obtained in up to 95 % yield.