M. Sindlerkulyk et al., SYNTHESIS AND PHOTOCHEMISTRY OF 2-STYRYLPYRROLES - INTERMOLECULAR PHOTOADDITION OF PYRROLES TO A DOUBLE-BOND, Recueil des travaux chimiques des Pays-Bas, 114(11-12), 1995, pp. 476
Irradiation of the 2-styrylpyrroles 3 and 5 resulted in intermolecular
addition of the pyrrole derivative to the double bond of a second mol
ecule in a regiospecific way to give the dimeric products 6 and 7 as t
he main products. The hi-methyl-substituted derivative 4 did not show
the same reaction, but reacts as the corresponding furan derivative.