Silver versus gold catalysis in tandem reactions of carbonyl functions onto alkynes: A versatile access to furoquinoline and pyranoquinoline cores
An efficient and versatile tandem process of acetalization and cycloisomerization reactions has been developed for the reactions of 1-alkynyl-2-carbonyl-quinoline substrates. The reaction occurs thanks to Au 1 and Ag1 catalysis. Silver(I) catalysis has been extensively studied (11 different silver species) on a broad range of quinoline derivatives (variation of alkyne substituent, of carbonyl function and of nucleophiles), leading to a variety of furoquinoline and pyranoquinoline moieties. An insight is given for the presumed mechanism along with DFT-B3LYP/6-31G** calculations to address the 6-endo and 5-exo regioselectivities observed.
Godet, Thomas,Vaxelaire, Carine,Michel, Carine,Milet, Anne,Belmont, Philippe