Which reagent converts propene to 1-propanol ?
- H2O, H2SO4
- B2H6, H2O2, OH-
- Hg(OAc)2, NaBH4/H2O
- Aq. KOH
Answer
(2) B2H6, H2O2, OH-
Solution
As per NCERT, hydroboration–oxidation of an alkene gives the alcohol with anti-Markovnikov orientation of the –OH group.
CH3-CH=CH2 + (H-BH2)2 CH3-CH2-CH2-BH2
⇒ (CH3-CH2-CH2)3B [OH-]H2O, H2O2 3CH3-CH2-CH2-OH + B(OH)3
∴ B2H6 followed by H2O2/OH- gives propan-1-ol.
(1) and (3) follow Markovnikov's rule and give propan-2-ol; (4) aq. KOH does not add to an alkene.
Answer: (2)