Trimethylenemethane dications

The trimethyl trihydroxy derivative of the trimethylenemethane dication (50) was observed under stable ion conditions." The dication 50 is the first Y-conjugated dication system experimentally observed. However, the question of the effect of the Y-conjugation... 

Attempted preparation of unsubstituted trimethylenemethane dication, 58, by treatment of 2-(chloromethyl)-3-chloropropene (57) with SbFs in SO2CIF at -120°C was also unsuccessful, further showing that the Y-aromaticity is unimportant in this system. 

Experimental evidence for the six electron systems has been described in Sect. 2.1.4. Skancke reproduced the relative stabihty of the cross conjugated systems relative to the linear isomers by calculating the trimethylenemethane and buta-l,4-diyl dianions [27] and their dilithio salts [28]. For the four electron systems butadiene is more stable than trimethylenemethane. Experimental examination of the relative stabihties of two electron systems using the trimethylenemethane and buta-14-diyl dications needs to overcome the intrinsic instabihties of dications dissatisfying the octet rule. 

---