Hi all, I have a question about diastereoselective reaction. From my understanding, a diastereoselective reaction is a stereoselective reaction producing diastereomers in unequal amount.
The following reaction is from my lecture material. It says the reaction is diastereoselective and the product is a diastereomer of 2-methylcyclohexanol.
However, hydroboration of alkenes is a syn addition of H-BH2 to the alkene. If H-BH2 is added from the top face of the alkene, A will be formed. If H-BH2 is added from the bottom face of the alkene, B will be formed. A and B are enantiomers. Since a pair of enantiomers are formed, why is the reaction diastereoselective?
Please help, I am very confused about this. Thank you very much in advance.