D. Dauzonne et C. Grandjean, SELF-CONDENSATION OF ORTHO-HYDROXY-BETA-CHLORO-BETA-NITROSTYRENES - SYNTHESIS OF SOME NITROMETHYLENE-11H-BENZOFUROL[3,2-B][1]BENZOPYRANS, Journal of heterocyclic chemistry, 31(4), 1994, pp. 1021-1025
The triethylamine-promoted self-condensation of several 2-(2-chloro-2-
nitroethenyl)phenols gives the so far unknown Nitromethylene-11H-benzo
furo[3,2-b][1]benzopyrans.