Z. Riedl et al., UNUSUAL CONVERSIONS OF A ZWITTERIONIC POLYFUSED TRIAZINE WITH ELECTRON-DEFICIENT DIENOPHILES, Chemical communications, (8), 1997, pp. 757-758
Investigation of reactions of the zwitterionic polycycle I with electr
on-deficient dienophiles revealed that Michael addition products 3 and
4, selective cycloadducts 2 and, in a special case, a stable dimeric
radical cation 5 are formed.