the question is for the fallowing picture so how do we know what is the major product . I know we get two enantiomers but whats the major and whats not. thanks in advance :
Hey there! Thanks for the question :)
In these problems the major/minor product has to do with knowing if this will be a Markovnikov vs Anti-Markovnikov additon. In Johnny's videos on Hydroboration Oxidation that you can find here: https://www.clutchprep.com/organic-chemistry/hydroboration-oxidation we go over how this is an Anti-Markovnikov additon. That is all this question is asking! Therefore we would simply get an OH added to the least substituted side of our alkene. It is also a syn addition which means the H that we add would add on the same side of our OH group.
I hope this makes sense! If you want to review the mechanism just check out the link provided above!
Thank you :)