Hydroboration/Oxidation of an Alkene
Introduction: An alcohol can be added across the double bond of an alkene via hydration, which is the addition of a proton and alcohol group to the double bond. This reaction can yield either a Markovnikov alcohol or an Anti-Markovnikov alcohol. If the reaction is carried out in acidic conditions, the reaction yields a Markovnikov alcohol. The mechanism includes the formation of a carbocation intermediate, which has a lower activation energy when it is formed on the more substituted or resonance stabilized carbon. The nucleophile then attaches to the positive charge created by the carbocation, yielding the Markovnikov product. However, if the reaction is carried out via hydroboration (with diborane or …show more content…
Results: Starting volume of styrene: 1.7 mL Theoretical yield of 2-phenylethanol: 1.796 mL
Mass of 2-phenylethanol collected after rotovap: 1.408g
Volume of 2-phenylethanol collected: mass collected/density
Volume collected: 1.408g/(1.02g/mL)= 1.38 mL
Percent yield= (volume product/volume starting styrene) *100
Percent yield= (1.38 mL/ 1.7 mL)*100= 81.2%
Peaks on the product IR graph: Between 3300-3400 cm-1, 2800-3100 …show more content…
While both carbons in the double bond have the same substitution, the carbon closer to the aromatic ring is more sterically hindered. The less sterically hindered carbon requires less energy to form the borane intermediate, therefore 1-phenyl-2-propanol will form more readily than 1-phenyl-1-propanol using hydroboration and oxidation. If 1-phenylpropene was reacted with sulfuric acid, the major product would be 1-phenyl-1-propanol. In a hydration reaction in the presence of acid, a carbocation intermediate is formed and then attacked by a nucleophile. Since a carbocation intermediate is formed, the reaction will procedure in a manner to stabilize the positive charge. While both carbons of the double bond are secondary carbons, the first carbon can stabilize a positive charge more readily due to resonance. Since the carbocation intermediate is more stable, 1-phenyl-1-propanol will form more readily in acidic conditions compared to
Introduction: An alcohol can be added across the double bond of an alkene via hydration, which is the addition of a proton and alcohol group to the double bond. This reaction can yield either a Markovnikov alcohol or an Anti-Markovnikov alcohol. If the reaction is carried out in acidic conditions, the reaction yields a Markovnikov alcohol. The mechanism includes the formation of a carbocation intermediate, which has a lower activation energy when it is formed on the more substituted or resonance stabilized carbon. The nucleophile then attaches to the positive charge created by the carbocation, yielding the Markovnikov product. However, if the reaction is carried out via hydroboration (with diborane or …show more content…
Results: Starting volume of styrene: 1.7 mL Theoretical yield of 2-phenylethanol: 1.796 mL
Mass of 2-phenylethanol collected after rotovap: 1.408g
Volume of 2-phenylethanol collected: mass collected/density
Volume collected: 1.408g/(1.02g/mL)= 1.38 mL
Percent yield= (volume product/volume starting styrene) *100
Percent yield= (1.38 mL/ 1.7 mL)*100= 81.2%
Peaks on the product IR graph: Between 3300-3400 cm-1, 2800-3100 …show more content…
While both carbons in the double bond have the same substitution, the carbon closer to the aromatic ring is more sterically hindered. The less sterically hindered carbon requires less energy to form the borane intermediate, therefore 1-phenyl-2-propanol will form more readily than 1-phenyl-1-propanol using hydroboration and oxidation. If 1-phenylpropene was reacted with sulfuric acid, the major product would be 1-phenyl-1-propanol. In a hydration reaction in the presence of acid, a carbocation intermediate is formed and then attacked by a nucleophile. Since a carbocation intermediate is formed, the reaction will procedure in a manner to stabilize the positive charge. While both carbons of the double bond are secondary carbons, the first carbon can stabilize a positive charge more readily due to resonance. Since the carbocation intermediate is more stable, 1-phenyl-1-propanol will form more readily in acidic conditions compared to