CHEM 206 Test 3

- Markovnikov regioselectivity (Halogen added to most stable carbocation)
- No stereoselectivity (No stereochemical preference)
- Carried out by H-Br or H-Cl

- Markonovnikov regioselectivity (H3O+ is added to most stable carbocation)
- No stereoselectivity (No stereochemical preference)
- Carried out by H2O and H2SO4
- H2O catalyzes H3O+ to OH

- Watch out for secondary carbocations with adjacent tertiary or quaternary carbon center
- Secondary carbocations can become more stable if rearranged
- Hydrogen "slides over" and binds to the positively charged center

- Addition of Cl2 or Br2
- Carried out by CCl4, CH2Cl2, or no solvent
- No regioselectivity (Br or Cl is added to both sides)
- Stereospecific (Stereochemistry of reactants control products)
- Bridged halonium ion intermediate
- Anti-addition of X2 (Halogen attacks from the opposite side of the bridge)
- E forms meso(R,S + S,R) or Enantiomers(R,S + S,R)
- Z always forms enantiomers (S,S + R,R)

- Addition of HOX
- Carried out by X2 and H2O
- Regioselective (-OH to more stable carbocation)
- Stereospecific (Stereochemistry of reactants control products)
- Bridged halonium ion intermediate
- Anti-addition of -OH and -BR

- Net hydration (H-OH) without rearrangement
- No carbocation intermediate
- Carried out by Hg(OAc)2, H2O, and NaBH4
- Markonovnikov regioselectivity (H2O is added to most stable carbocation, Hg(OAc)2 on other carbon)
- Bridged mercurinium ion intermediate

- Carried out by BH3, H2O2, and NaOH
- Reverse Markonovnikov regioselectivity (OH is added to LEAST stable carbocation)
- Stereospecific
- Syn-addition of OH and H

- Oxidation by OsO4
- Carried out by OsO4 and H2O2
- No regioselectivity (OH added to both carbons)
- Syn-addition of OH to both carbons

- Cleaves C=C double bond and forms carbonyl groups
- Carried out by O3 and (CH3)2S

- Alkenes are reduced to alkanes by H2
- Carried out by H2 and transition metal catalyst
- Gets rid of double bond
- Syn-addition dominates over anti-addition

- Taking an alkane and substituting hydrogen with a halogen (Usually Br or Cl)
- Substitution reaction
- Requires initiation by light or heat and peroxides
- Regioselectivity (Tertiary Hydrogen > Secondary Hydrogen > Primary Hydrogen)

- Carried out by N-Br (NBS) and CCl4
- Double bond is kept
- Replaces one allylic hydrogen with Bromine from the highest degree of carbon
- Major is the most stable structure based on resonance (Check by substituted double bond ex. mono, di, tri, higher subsituted double bond = more stable)

- Carried out by H-Br, CCl4, and peroxide (radical initiator)
- Reverse Markovnikov regioselectivity (Br is added to LEAST stable carbocation)
- Bromine atom is added to give the most stable radical

- transition state resembles reactants in exothermic reactions
- transition state resembles products in endothermic reactions