[starry]

I have two compounds:
#1

#2


And I need to explain why the second compound undergoes an SN1 reaction more rapidly..

Is this because it can resonate? I think there is more to it. Could anyone help?

[azmanam]

resonance is key.  what about resonance makes 2 a better answer than 1?

[sanderol]

ditto, the only thing I can think of besides resonance is that #2 is better approachable to a nucleophile since it's flatter.

But resonance is the key.

[sjb]

ditto, the only thing I can think of besides resonance is that #2 is better approachable to a nucleophile since it's flatter.

But resonance is the key.

That would not be a problem in an S_N1 mechanism.

[Rishi]

Well, I would think that resonace is the key and secondly I would also think that because of the double bonds, the steric factor reduces and thus making it more favorable for SN1 type reactions. So in a way I would agree with Sanderol

[nj_bartel]

RDS in an S_N1 is dissocation of the LG typically.

[carboneel]

i think that because of sulfur's available 2 pairs of e-, one of them moves down to the tetrahedral carbon and the 2e- bonding the Cl to said carbon leave with the Cl, (or the e- leaves with the Cl first and then the reverse happens) either way, the ring is stabilized by resonance  (aromaticity: odd number of pairs of e-, planar, cyclic [though there are exceptions]) so if you drew out the resonance contributors you should get ortho and para subst. with respect to the sulfur.
-hope that helps

[ufalynn88]

as a couple people have said, molecule 2 is favored towards SN1 over molecule 1 simply due to the intermediate. The RDS of SN1 is the leaving of the leaving group, and the 2nd molecule provides an additional resonance structure (due to the double bond 1 carbon away from the carbon with the Cl on it)