155590-65-1Relevant articles and documents
Metal-free one-pot synthesis of benzofurans
Ghosh, Raju,Stridfeldt, Elin,Olofsson, Berit
, p. 8888 - 8892 (2014/07/22)
Ethyl acetohydroxamate was efficiently arylated with diaryliodonium salts at room temperature under transition-metal-free conditions. The obtained O-arylated products were reacted in situ with ketones under acidic conditions to yield substituted benzo[b]furans through oxime formation, [3,3]-rearrangement, and cyclization in a fast and operationally simple one-pot fashion without using excess reagents. Alternatively, the O-arylated products could be isolated or transformed in situ to aryloxyamines or O-arylaldoximes. The methodology was applied to the synthesis of Stemofuran A and the formal syntheses of Coumestan, Eupomatenoid 6, and (+)-machaeriol B. Just add salt! A metal-free, room temperature arylation of ethyl acetohydroxamate, followed by an in situ reaction with ketones under acidic conditions yielded substituted benzo[b]furans in a fast and operationally simple one-pot fashion without using excess reagents (see scheme). Alternatively, the O-arylated products could be isolated, hydrolyzed in situ to aryloxyamines, or transformed to O-arylaldoximes. The efficiency of the methodology was demonstrated by the formal synthesis of several biologically active benzofurans.
