Addition rxns

Question 1

```Add Br to more substituted C

Answer 1

• HBr/HCl
• Proton transfer from double bond
• then nucleophilic attack

Question 2

anti-markovnikov hydrohalogenation

Answer 2

• Add Br to less substituted C
• HBr/HCl and ROOR
• enantiomers if chiral center formed

Question 3

Add OH to more substituted C

Answer 3

• H<sub>3</sub>O<sup>+</sup>, then water as a base
• dilute acid favors addition
• Rearrangement is possible
• enantiomers
• proton transfer, nucleophilic attack, proton transfer

Question 4

Markovnikov addition of OH w/o rearrangement

Answer 4

1. Hg(OAc)<sub>2</sub>, H<sub>2</sub>O
2. NABH<sub>4</sub>

Question 5

anti-markovnikov addition of OH

Answer 5

• syn-addition H and OH
  
  • both enantiomers
• THF can stablize BH<sub>3</sub> by donating electron density into the empty p orbital of boron

1. BH<sub>3</sub>•THF
2. H<sub>2</sub>O<sub>2</sub>, NaOH

• Syn addition- 2 enantiomers w/ 1 or 2 chiral centers

Question 6

addition of 2 H’s

Answer 6

• Syn addition

H<sub>2</sub> and Pt

• enantiomers formed
• symmetrical alkenes produce a meso compound

Question 7

anti addition of X<sub>2</sub>

Answer 7

• F<sub>2</sub> too violent and I<sub>2</sub> too slow
• Br<sub>2</sub> or Cl<sub>2</sub>
• Nucleophilic attack and loss of leaving group to bridging bromium ion+
• then nucleophilic attack

Question 8

add bromine and OH

Answer 8

• anti addition
• OH on more substituted position
• Br<sub>2</sub> and H<sub>2</sub>O
• nucleophilic attack–toδ+ Br– and loss of leaving group
• then nucleophilic attack and finally proton transfer

Question 9

Anti addition of OH’s

Answer 9

• forms an epoxide, three membered cyclic ether

1. RCO<sub>3</sub>​H, peroxyacetic acid, MCPBA
2. H<sub>3</sub>O<sup>+</sup>

Question 10

syn addition of OH’s

Answer 10

1. OsO<sub>4</sub>
2. NMO

or

1. cold potasium permanganate under basic conditions

Question 11

cleave C=C bond

Answer 11

1. O<sub>3</sub>
2. DMS or Zn/H<sub>2</sub>O

Question 12

strength of a Nucleophile

Answer 12

• greater neg. charge–stronger nucleophile
• more polarizable

Question 13

asymmetric hydrogenation

Answer 13

• a chiral catalyst can produce one enantiomer over another
• BINAP