23I ??
5 Answers
23oxygen can also take part in delocalisation in that allylic carbocation ,
i.e CH3 --O+=CH -- CH=CH2 <---> CH3--O--CH=CH-CH2+ <---> CH3--O--CH+--CH=CH2
1watch out!!!! same delocalization is possible in II too......what i felt was different in two cations is distance b/w +ve carbon and methoxy gp......so -I effect takes lead here........making I more satble[lesser -I effect]
23yeah thats wat i mentioned , delocalisation is possible of course in both , but in 1 , i specifically mentioned dat " oxygen can also take part in delocalisation "
yeah your arguement can hold true , but a stronger reason would be that I has more canonical forms , and there is more delocalisation than that in II .
Further more
see if u draw the 2 canonical forms of II, u will find that not all atoms have a complete octet in any of the 2 canonical forms ,
whereas in I, u will find that in the first canonical form that i hav drawn , all atoms have a complete octet , incluing the positively charged oxygen , and hence it is stable enough [1]