Here is a quiz question from Billing & Brinker (DOI). What do you get when you react tetrahydrofuran in chloroform with 2 equivalents of tetrabromomethane and triphenylphosphine? Answer: 1,4-dibromobutane, tetrabromomethane, triphenylphosphine oxide and Ph₃PCBr₂. On the left the electron pushing to prove it.

The reaction is similar to the Appel reaction and the Corey-Fuchs reaction but somehow chloroform itself does not take part in the reaction. Patience is called for in the published procedure: reaction time 10 days.