Chemoselective synthesis of m-teraryls through ring transformation of 2H-pyran-2-ones by 2-(1-arylethylidene)-malononitriles

We have developed a simple, efficient and chemoselective approach for the synthesis of m-teraryls by the reaction of 6-aryl-2-oxo-4-(sec.amino)-2H-pyran-3-carbonitriles and 2-(1-arylethylidene)malononitriles under basic conditions. We used 6-aryl-2-oxo-4-methylsulfanyl-2H-pyran-3-carbonitriles as precursors and successfully afforded 5'-methylsulfanyl-[1,1';3',1 '']teraryl-4'-carbonitriles. We tried to understand the difference in the reactivity of structurally symmetrical molecules, such as allyl cyanide, 2-cyanomethylbenzonitrile and 2-(1-arylethylidene)malononitrile. The structure of 4 ''-methyl-5'-(piperidin-1-yl)-[1,1':3',1 ''-terphenyl]-4'-carbonitrile was confirmed by single crystal X-ray diffraction analysis.