Question

State the concept or idea in a single sentence or two. Clearly and succinctly state the concept. Elaborate on the concept ("In other words...") Explain/exemplify why that happens on a molecular level and/or give concrete examples and counter examples) of the concept. ("This happens because..." and/or "For example, ...) illustrate the concept with a picture, diagram, metaphor, or analogy. Generalize the concept. Give a comparison, metaphor, or picture-in-words to bring it home. ("This is like ...) 2. (10 pts) Use the SEE-i technique to explain one of the concepts below. The first worked problem will be graded if no choice is clearly indicated. a. Two specific hydration reactions are shown below: oxymercuration-demercuration and hydroboration-oxidation. These two reactions give opposite regiochemistries and stereochemistries as the major product of their respective reactions. To earn full credit, the illustration portion of your explanation must include a drawing of the important steps in the mechanisms that cause the different regiochemistries and stereochemistries. (remember "Dis deuterium: it's a way to "label" hydrogens and see the stereochemistry on an otherwise achiral carbon) (+ entantiomer) 1) Hg(OA), H.O. 2) NaBH -D ) BH, THE 2) H.O., OH H:0, OH OH (+ entantiomer) b. Explain Markovnikov's Rule. c. Explain how and why a carbocation might rearrange.

Answer 1

OXYMERCURATION - DEMERCURATION REACTION:

STEP-I (Mercuration) И . Aso-a-ona , , - оке кое сиз :0ң, он -OAC - од more stable attack 3° Carbocation) STEP - ercurat н-0-н чh Наво, +4+0 он Он 애 H H t. . н Н fren Ho-OAC Product (Anti-addition)

HYDROBORATION - OXIDATION REACTION:

Hydroboration H BH2 Syn addition) (وامع مهره 3) Horor o 2,14 (major) + би (maja) Hongo Ho fine Bluz OH oxidation

MARKOVNIKOV RULE: It states that the negative part of the adding molecule to the alkene gets attached to that carbon which is more substituted ( has lesser number of hydrogen atoms )

For example:

Br HC-CH=CH2 + HBr markere ov e -CH-CH3 (major product) (Propene) (Hydsogen 2-Bromo propane Bromide) MECHANISM : C- CH=CH2 + 4 he-er - CHg (more stable carbocation) ₂c-c1-ers & Br Hences - CH3 (major) Br

A carbocation is an intermediate which is formed during organic chemical reactions. There might also be rearrangements of carbocation from less stable form to more stable form that can be seen during the reaction.

For example: if in a reaction a secondary carbocation is formed and there is a chance of rearrangement of carbocation to give a tertiary carbocation which is more stable then rearrangement may occur.

te (1) Shift, da do carbocation 3o catbocation (more stable) [Carbocation rearrangement]