Question

Answer the following questions about radical halogenation

QUESTION 1 Performing allylic bromination of an asymmetric alkene produces two regiochemical outcomes due to resonance, and two conformations (R) and (S) for each chirality center produced. This is further complicated if you make the mistake of using Br2 as your source of bromine radicals, as the addition reaction producing alkyl dibromides competes with the allylic bromination. Br2, hv ???

Answer 1

*Allylic bromination is the addition of a bromine atom to the allylic position of a double bond rather than to the double bond itself. The most common reagent used for allylic bromination is N-bromosuccinimide (NBS). Bromine molecule usually adds across the double bond to form an adduct.

*An adduct is a product of the addition of 2 or more distinct molecules containing the atoms of all the added molecules.

*Here the order of the names of the 10 molecules given is
bu - H' where t is the hudengen radical it can undergo pesonance as follows (A) (8) This creates anothes allylic radical Both (A) & (B) could undergo bromination Seactices to form the peoducts as follows,

1. 19 20 21 22 23 26 27 28 29 30 Bo November (321-044) Week BT2 t Br Note: Br₂ - y Br+ Bo Bromine radical . B72 Pointyousotros BA Bola are the The above peoducts test 3 molecules the question.

2) Bromination addition peoducts Cadducts) all foomed when Br2 is added across the double bond. This is the most probable seaction when Br2 is eed as the reagent. Brz .. BO W 10 C The 4th & above 2 molecules are the 5th molecules in the question.
,

1. A

2. A

3. A

4. B

5. B

6. C

7. C

8. C

9. C

10. C