amines and nucleobases have also been used, affording the corresponding coupling products in good to excellent yields. Moreover, this method has been employed for chemoselective C–N arylation of aminophenols and further utilized for the synthesis of carbazole natural products, avoiding the protection and deprotection steps.
Copper-Catalyzed NH Insertion and Oxidative Aromatization Cascade: Facile Synthesis of 2-Arylaminophenols
作者:Dong Ding、Xiaobing Lv、Jian Li、Guangyang Xu、Bing Ma、Jiangtao Sun
DOI:10.1002/asia.201402080
日期:2014.6
A copper‐catalyzed cascade reaction of N‐Hinsertion and oxidativearomatization has been developed. 2‐Arylaminophenols have been prepared in moderate to high yields from the diazo substrates. Moreover, this newly established methodology allows efficient access to natural 1‐oxygenated carbazole alkaloids, such as glycozolicine and murrayafoline A.
EXO-2-oxazolidinone dienes in the regioselective synthesis of natural carbazoles, 6-methoxymurrayanine ( 6) and clausenine ( 7), is described. The regioselective cycloaddition of novel diene 10 to acrolein by Lewis acid catalysis provided adduct 12, which after aromatization gave benzoxazolone 14 as the key intermediate for the preparation of both carbazoles. A straightforward and efficient synthesis of 7 was