Yesterday at 2:17 pm, a supposedly clean SN1 on a secondary chloride in acetone detoured via a hydride shift, leaving me with 43% of the rearranged isomer and a lonely TLC spot I couldn’t justify. Does anyone else feel attacked when Curtin–Hammett shows up uninvited and your ‘synthesis method’ becomes ‘explain the mechanism to the PI’?
That ‘hydride shift’ screams cation lifetime — convert chloride to tosylate and push SN2 instead; agreed?
I’ve had the same struggle with unexpected rearrangements during SN1 reactions. I found switching solvents helped; try using DMSO instead of acetone — sometimes it reduces side reactions. Have you considered adjusting the temperature?
That hydride shift feels like a surprise guest at a party, right? Maybe next time try warming your reaction a bit; it might help push the pathway you want. Have you considered tweaking the nucleophile as well?