Assembly of 3-(trifluoromethyl)thiochromenes via a regioselective trifluoromethylthioarylation of (3-arylprop-2-ynyl)oxybenzenes with trifluoromethanesulfanylamide

An intramolecular electrophilic cyclization of (3-arylprop-2-ynyl)oxybenzenes with trifluoromethanesulfanylamide is reported, which affords 3-(trifluoromethyl)thiochromenes in good yields with high regioselectivity. The reaction works efficiently in the presence of 2.0 equiv of bismuth chloride, and different functional groups can be compatible under the conditions. The related (3,4-dihydronaphthalen-2-yl) (trifluoromethyl)sulfane and 3-((trifluoromethyl)thio)-1,2-dihydroquinoline can be generated as well. Preliminary mechanistic studies reveal that the presence of bismuth chloride would promote the formation of ‘CF3S+’, which would then activate the triple bond of substrate, thus facilitating the intramolecular electrophilic 6-endo cyclization.

An intramolecular electrophilic cyclization of (3-arylprop-2-ynyl)oxybenzeneswith trifluoromethanesulfanylamide is reported, which affords 3-(trifluoromethyl)thiochromenes in good yields with high regioselectivity in the presence of 2.0 equiv BiCl3.Figure optionsDownload as PowerPoint slide