Synthesis of (±)-cis-1-Aryl-3-oxo-2,3-dihydro-1H-benzo[f]chromene-2-carbonitriles and (±)-trans-4-Aryl-2-oxo-3,4-dihydro-2H-benzo[h]chromene-3-carbonitriles

The unexpected stereospecific synthesis of (+/-)-cis-1-aryl-3-oxo-2,3-dihydro-1H-benzo[f]chromene-2-carbonitriles (2) and (+/-)-trans-4-aryl-2-oxo-3,4-dihydro-2H-benzo[h]chromene-3-carbonitriles (4) from (+/-)-3-amino-1-aryl-1H-benzo[f]chromene-2-carbonitriles (1) and (+/-)-2-amino-4-aryl-4H-benzo[h]chromene-3-carbonitriles (3), respectively, by reacting them in formic acid (88%), at reflux, is reported. A DFT analysis has been applied with success to justify these highly stereospecific reactions.