Hydroboration-Oxidation of (1R)-(+)-aplha-Pinene - Lab Report Example

Hydroboration-Oxidation of (IR Alpha-pinene The objective of the experiment was to undertaken an hydroboration-oxidation of an IR – (+) –alpha-pinene in order to form an alcohol product. The procedure began by drying all the experimental materials ranging from the glassware to heating materials. The experiment began by mixing the alkene with tetrahydrofuran and exposing it to heat. The resultant solution was then cooled in an ice-bath, followed by the oxidation reaction. The oxidation reaction was performed by adding water, petroleum ether and HCL bit by bit, each time removing the aqueous layer formed, while saving the organic layer.

The final step involved subliming the organic layer with an attempt to purify the products through use of a cold finger and a vacuum. The final product was then observed and measurements taken. IntroductionThe experiment involved conversation of alkenes into alcohol through the process of anti-markovnikov. The reaction performed exhibited stereo-selectivity and region-selectivity. The solutions used in the experiment were chemically air-sensitive, this made addition of the compounds used a crucial step.

The experiment facilitated the learning of how to use IR-spectroscopy in process of confirming the conversion of an alkene group to alcohol group. The corpus of hyroboration of an alkene entails the addition of borane through a double bond. This is an oxidation process that leads to formation of an oragnoborane intermediate. The intermediate, through anti-Markovnikov hydration process, gives an alcoholic product. During the process of the reaction, the boron adds towards the fewer substitutes, which is carbon, owing to the fact that it has a higher level of electromagnetivity.

The reaction involving hydrogen peroxide and sodium hydroxide leads to the production of hydro-peroxide anions, removing the boron atom, thus forming boron-hydroperoxide. The alkyl group reacts with the oxygen atom and simultaneously the hydroxide forms another hydroperoxide anion. This process occurs several times until a C-O bond s formed by converting all the C-B bonds. A hydrolysis of the C-O bonds leads to the formation of alcohol. 1) The melting point of my product was at 55.8 degree Celsius.

This is lower than the melting point of water, which is usually at 100 degree Celsius at normal temperature. This is higher than the melting point of isopinocampheol, which is at 51. 53 degree Celsius: This is similar to the melting point of neoisopinocampheol. It is also higher than the melting point of cis-2-pinanol and that of trans-2-pinanol, which are at 43 and 52 degrees Celsius respectively. My product seems to possess stronger inter-molecular forces, holding the hydrogen ions together, thus a higher melting point.

In relation to stereo-selectivity, my product indicates a higher sense of stereo-selectivity. This can be attributed to the high level of syn-addition of boron and hydrogen atoms to the carbon-carbon double bond. This attraction could be the cause of its higher melting point as compared to others. My product is seemingly highly regioselective, the essence of its higher melting points as compared to others could be attributed to the higher rate at, which hydrogen atoms prefer the double carbon-carbon bond, thus an increased level of melting point. 2) An observation of the infrared spectroscopy exhibited a big difference between the rate of vibration between alcohol molecules and the 1R – (+)- α- pinene.

The highest absorption peak in the spectrum is approximately at 997cm-1. 3) An additional test that can be used to differenciate the alkene and the alcohol entails the use of sodium test. With the addition of sodium metal, the alcohol produces hydrogen gas while the alkene does not produce any gas. 4) Question 6-88a) Function of BH3 as it forms the complexBorane, BH3, chemically adds to the double bond. This automatically transfers one hydrogen atom to the nearby carbon than bonds with the boron.

This is referred as hdroboration. b) Structure of Borane, BH3H B H H 6-89a) Reasons why Borane reacts readily with the π- electron system of an alkeneBorane is characterized by a neutral molecule. It has six electrons that are shared within its valence shell, thus making it an electrophile. The essence of electrophile, makes borane chemically capable of accepting a pair of other electrons in order to complete its octet structure. Alkenes usually undergo experience electrophillic reactions through an addition of electrophile, i.e. Borane. b) Reasons why Diborane Reacts slowly with Double-Bond CarbonDouble bond carbons are held together by stronger double bond covalent bonds.

This slows down its addition reaction with diborane. 6-90Explanation for the ratio givenBoron adds easily to the least substituted carbon atom owing to the fact that the hydrogen atoms are not the electrophile, but boron. The ratio can also be attributed to the fact that boron by-products usually depend on the number of borane atoms applied to facilitate the reaction of the alkene i.e. one borane could be used to hydroborate upto approximately 3 alkenes. 6-91Upon the addition of an acidic reagent to the hydroboration process, a proton is transferred to the alkene.

This leads to the formation of a carbocation. The acid contains a hydroxyl group that attaches to the less substituted carbon group: This lead to a change in the resultant structure of the carbon structure. Work CitedBrown, Herbert C.. Hydroboration. New York: W.A. Benjamin, 1962. Print. Koten, Gerard van. Organometallic pincer chemistry. Berlin: Springer, 2013. Print.