Which will be more stable carbocation upon heterolysis of #"C"-"Cl"# bond?

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1 Answer
Mar 23, 2018

Consider the consequence of the heterolysis you describe for each, in turn,

#(1)#puu.sh

This would be stabilized by resonance,

puu.sh

#(2)#puu.sh

The cyclic ether would be acting as an electron donating group, stabilizing the positive charge.

#(3)#puu.sh

This is stabilized by hyperconjugation to the highest degree (#3°#).

#(4)#puu.sh

This is a primary carbocation: a very unstable molecule.

As a result of this qualitative analysis, #(1)# and #(3)# are very close in stability, but I would wager #(1)# is slightly more stable. Resonance is a very powerful effect.