4-bromobutane-1-thiol in the presence of a strong base such as NaH (sodium hydride, hydride [H-] is the base) will give an SN2 mechanism and produce tetrahydrothiophene, 99% of the time.
Although, 1% of the time you'll make but-1-ene-4-thiol. Can someone explain to me why, and explain how the mechanism works. I know how tetrahydrothiophene's mechanism, but not the but-1-ene-4-thiol. If someone could help, I'd appreciate it.