Abstract:
Molecular iodine was discovered highly effective as catalyst for the Friendel-Crafts alkylation of electron-rich aromatic or heteroaromatic compounds with a wide varity of aldchydes in toluene at ambient temperature under 'open flask' and mild conditions. In the presence of 10 mol% of iodine, electron-rich aromatic or heteroaromatic compounds reacted with aromatic aldehydes regioselectively leading to the formation of the corresponding triarylmethane or diheteroarylarylmethane derivatives with moderate to excellent yields. On the other hand, series of diarylalkane or diheteroarylalkane derivatives was smoothly synthesized by reaction with aliphatic aldehydes. Moreover, the utility and applicability of this method for the synthesis of three bioactive triarylmethanes i.e. 4,4'-dihydroxytriphenylmethane, 4-chlorophenyl bis (4-hydroxyphenyl) methane and 1,1'-(((4-chlorophenyl) methylene)-dinaphthalen)-2-ol varying the aldehyde and arene motifs were accomplished. In each case, exclusive triarylmethanes selectively was observed and no by product was formed.