Which of the following additions to alkenes occur(s) specifically in an syn fashion?

Question

Quizplus · Accepted Answer

Dihydroxylation using OsO4 followed by reduction with NaHSO3, H2O yields a syn addition of two hydroxyl groups to the alkene. Addition of HSCH2CH2SH (ethanethiol) also occurs in a syn fashion. Hydroboration with BH3 followed by oxidation with H2O2 and NaOH also results in a syn addition of a hydroxyl group and a hydrogen atom. Therefore, options A, B, and C all involve syn additions to alkenes. Addition of HCl does not occur in a syn fashion, so option D is not correct.

Which of the Following Additions to Alkenes Occur(s) Specifically in an Syn