What is stereo structural IUPAC name of the following compound?

Configuration at #"C-2"#

The Cahn-Ingold-Prelog priorities of the groups on #"C-2"# are

#"Br = 1; C-3 = 2; C-1 = 3; H = 4"#

The #"H"# atom is furthest from our eye, and the 1 → 2 → 3 direction is counterclockwise.

Thus, the configuration at #"C-2"# is #S#.

Configuration at #"C-3"#

The Cahn-Ingold-Prelog priorities of the groups on #"C-3"# are

#"Cl = 1; C-2 = 2; C-4 = 3; H = 4"#

The #"H"# atom is closest to our eye, and the 1 → 2 → 3 direction is counterclockwise.

The configuration at #"C-3"# appears to be #S#.

However, because the #"H"# atom is closest to our eye, we invert the assignment.

The configuration at #"C-3"# is #R#.

The name of the compound is, therefore, (#2S,3R#)-2-bromo-3-chlorobutane.

NOTE:

Your image was the PubChem structure for (#2S,3S#)-2-bromo-3-chloro-butane.

They give three structures.

Wedge-Dash

(From PubChem)

This is the (#2S,3S#) isomer.

Wire Frame

This is the structure you give.

Amazingly, PubChem is incorrect. This is the (#2S,3R#) isomer.

3-Dimensional

(From PubChem)

This is the correct (#2S,3S#) structure.