[robvba]

1,3-dibromo-3-methylpentane + N₃^- (in THF) a six member ring structure consisting of three Ns?
sodium azide is a weak base, so it will displace the brimine. however, will it form a ring?

[408]

No, it will displace the bromine because it is a really strong nucleophile. Not because it is a weak base.

Look at it SN2ing off the terminal Br, and then the lone pair on the other side of the azide(formally - charged) knocking off the central Bromide ion.  Follow it up with the Br- ion eliminating the proton on carbon one with e- pushing taking care of the positive charge on the central N...and you get your desired cpd.

[robvba]

makes sense. thank you