Why do molecules named as (2S,3R)-2,3-dibromopentene?????

1 Answer
Jan 20, 2018

Why? Because each carbon atom with #CR_1R_2R_3R_4# substitution is capable of optical isomerism...

Explanation:

You gots....

#H_3C-stackrel(2)CHBr-stackrel(3)CHBr-CH_2-CH_3#

Carbons #2# and #3# each have 4 different substituents....they could be right-handed or left-handed. And as the chiral centres are NOT symmetrically substituted #RS!=SR#...and there are thus four potential optical isomers...#"RR"#, #"SS"#, #"RS"#, and #"SR"#.... Here we specify the one diastereomer....