This is a typical Julia-Kocienski reagent, which is used in a modified Julia-olefination (Julia-Kocienski-olefination).
The tetrazole sulfone is generally installed by substituting a hydroxyl group for this sulfide (see below) using the Mitsunobu-reaction, followed by oxidation with H
2O
2 to obtain the sulfone.
If I remember correctly, the Julia-Kocienski has indeed a high preference for the (E)-alkene product and is compatible with many functional groups.